diff --git a/.gitignore b/.gitignore
index e6931114..6dec3000 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,141 +1,83 @@
-############################
-# 1. GENERAL ARTIFACTS    #
-############################
-
-# Temporary files from the operating system
-# Ignore macOS-specific files
+##################################
+# 1. SYSTEM & LOGS               #
+##################################
 .DS_Store
-# Ignore Windows-specific files
 Thumbs.db
-# Ignore system cache files
 *.bak
 *.swp
 *~
 *.log
-
-# Compressed files that are usually large and can be recreated
-*.tar.gz
-*.zip
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
 
 ##################################
-# 2. DEPENDENCIES & MODULES      #
+# 2. DEPENDENCIES                #
 ##################################
-
-# Node.js / JavaScript
-# Ignore the folder containing all downloaded project dependencies.
-# This folder is too large and will be recreated by 'npm install'.
 /node_modules/
-
-# PHP / Composer
-# Ignore the Composer dependency folder.
 /vendor/
-
-# Python
-# Ignore virtual environments.
 .venv/
-/env/
 /venv/
 
 ##################################
-# 3. BUILD & COMPILATION TARGETS #
-
-# Test/Playwright reports (added by cleanup)
-playwright-report/
-test-results/
+# 3. BUILD & ARTIFACTS           #
 ##################################
-
-# Frontend (Vite, Webpack, etc.)
-# Ignore the final build output (the "finished" code for production).
+# Production builds
 /dist/
 /build/
-/temp/*
-!/temp/.gitkeep
+/target/
 
-# Build caches
-# Ignore Vite or other build caches.
+# Local/Temp caches
+.cache/
 .vite/
-# Ignore caches for Next.js/Gatsby/etc.
 .next/
-.cache/
+/coverage/
+*.tsbuildinfo
 
-# our temporary compilation caches and scratch files
+# Project specific temp folders (runtime artifacts)
+/temp/*
+!/temp/.gitkeep
 /cache/
-undefined
-benchmark-cache.ts
-scripts/bench-sandbox.ts
+/test-results/
+/playwright-report/
+/screenshots/
 
-# Java / Maven / Gradle
-/target/
+# Old archive folder (legacy, use /docs/archive instead)
+/archive/
 
 ##################################
-# 4. DEVELOPER TOOLS & EDITORS   #
+# 4. COMPILER & TYPESCRIPT       #
 ##################################
-
-
-# Local or temporary folders for individual tests
-.local/
-tem/
+# Ignore compiled JS only in source directories (not in root configs)
+client/src/**/*.js
+server/**/*.js
+shared/**/*.js
+!**/*.config.js
+!**/eslint.config.js
+!**/vite.config.js
 
 ##################################
-# 5. SENSITIVE DATA (SECURITY)   #
+# 5. ENVIRONMENT & SECURITY      #
 ##################################
-
-# Environment variables
-# ESSENTIAL: Ignore the file containing sensitive data (API keys, passwords).
 .env
-# Ignore local/test versions of the .env file.
-.env.local
-.env.development.local
-.env.test.local
-.env.production.local
+.env*.local
+.vercel
 
 ##################################
-# 6. SERVER-SPECIFIC ARTIFACTS   #
+# 6. STORAGE & DB (SIMULATION)   #
 ##################################
-
-# Public or temporary files potentially created on the server
-# If 'server/public' only contains auto-generated files, ignore:
-# server/public/
-# If 'server/public' contains hand-written assets (images, favicons), DO NOT ignore.
-
-# Ignore database files if they are kept locally (e.g., SQLite)
 *.sqlite
 *.db
+/storage/*.json
+!/storage/.gitkeep
 
 ##################################
-# 7. TYPESCRIPT ARTIFACTS        #
+# 7. DOCUMENTATION & REPORTS     #
 ##################################
-
-# Ignoriere generierte JS-Dateien in TS-Projekten
-# (Verhindert das "Verschmutzen" der Quellordner)
-*.js
-*.js.map
-*.d.ts
-
-# Aber: Important configuration files SHOULD NOT be ignored
-!tailwind.config.js
-!postcss.config.js
-!jest.config.js
-
-# TypeScript build information
-# Caches created by TypeScript Compilern.
-*.tsbuildinfo
-
-# Coverage reports (Vitest)
-/coverage/
-.vercel
-.env*.local
-
-UNOWEBSIM_gitlab/
-
-# Runtime artifacts
-logs/
-temp/
-*.log
-run-tests_output.log
-# test-results folder is already covered earlier but repeat for clarity
-test-results/
-
-# Measurement reports (werden bei Bedarf neu erzeugt)
+# Temporary one-off reports are archived in /docs/archive/
+# Binary reports and benchmarks should not be committed
+*.csv
 font_size_report_*.md
-font_size_report_*.csv
\ No newline at end of file
+benchmark-*.json
+# but keep /docs/archive tracked since it contains organized archives
+
diff --git a/.vscode/settings.json b/.vscode/settings.json
index cab70e77..f34db3a7 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -132,6 +132,9 @@
     "/^python3 \\./temp/write-cli-test\\.py$/": {
       "approve": true,
       "matchCommandLine": true
-    }
+    },
+    "/bin/ls": true,
+    "/usr/bin/git": true,
+    "test": true
   },
 }
diff --git a/EVENT_DRIVEN_OPTIMIZATION.md b/archive/clean-up-2026-03-06/EVENT_DRIVEN_OPTIMIZATION.md
similarity index 100%
rename from EVENT_DRIVEN_OPTIMIZATION.md
rename to archive/clean-up-2026-03-06/EVENT_DRIVEN_OPTIMIZATION.md
diff --git a/PERFORMANCE_AUDIT.md b/archive/clean-up-2026-03-06/PERFORMANCE_AUDIT.md
similarity index 100%
rename from PERFORMANCE_AUDIT.md
rename to archive/clean-up-2026-03-06/PERFORMANCE_AUDIT.md
diff --git a/SPEED_BOOST_FINAL_REPORT.md b/archive/clean-up-2026-03-06/SPEED_BOOST_FINAL_REPORT.md
similarity index 100%
rename from SPEED_BOOST_FINAL_REPORT.md
rename to archive/clean-up-2026-03-06/SPEED_BOOST_FINAL_REPORT.md
diff --git a/archive/clean-up-2026-03-06/TODO.md b/archive/clean-up-2026-03-06/TODO.md
new file mode 100644
index 00000000..cf443ba8
--- /dev/null
+++ b/archive/clean-up-2026-03-06/TODO.md
@@ -0,0 +1,42 @@
+# Not Completed
+
+## Features
+- Better Analog Input UI
+- Better Autocomplete/Linting
+- Autosaving so that you do not loose code when browser refreshes
+
+
+
+## Bug Fixes
+
+
+
+# Completed
+
+## Features
+- Soft cursor movement
+- Serial Plotter
+- Enhanced Parsing
+- Visualize the arduino board svg in transparent when simulation not running
+- Ability to pause the running sketch
+- Debug Console
+- Batching of pin states: collect pin states with timestamps and send them together / decode in frontend
+- Batching of serial messages / decode them in frontend
+- Frontend rendering fpr serial output
+
+## Bug Fixes
+- Toggle visibility PWM button
+- Multiple selections in example menu
+- X-Button (output-panel) should be on the right side and the same button-style like the other icon-buttons
+- PWM-Toggle-Button must be square like the other icon-buttons
+- The margin of all button should be enlarged
+- Example Menu: Only show one mared item (green) never more than one
+- Example Menu: When opening a tree node, close other tree nodes!
+- Pause/Resume functionality: digitalRead() returning wrong values, no serial output, timing frozen (Fixed: Added atomic pause state and offset tracking)
+- PIN_MODE/PIN_VALUE messages triggering onError incorrectly
+- Timing issue: delay(1000) in loop() needs 1200ms! (Fixed: removed stdin polling overhead from delay())
+- Screenshots in README.md again with updated images (Fixed: Added 3 updated screenshots)
+- Tables (IO-Registry and Debug): records hit header when scrolling. Header should be above the records not on them.
+- When pinMode ist programmed twice or more for one pin, it should create a message in messages
+
+
diff --git a/WORKER_PROTOCOL_STRICT_TYPES.md b/archive/clean-up-2026-03-06/WORKER_PROTOCOL_STRICT_TYPES.md
similarity index 100%
rename from WORKER_PROTOCOL_STRICT_TYPES.md
rename to archive/clean-up-2026-03-06/WORKER_PROTOCOL_STRICT_TYPES.md
diff --git a/archive/clean-up-2026-03-06/screenshots/screen1.png b/archive/clean-up-2026-03-06/screenshots/screen1.png
new file mode 100644
index 00000000..37f10fbf
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diff --git a/archive/clean-up-2026-03-06/screenshots/screen2.png b/archive/clean-up-2026-03-06/screenshots/screen2.png
new file mode 100644
index 00000000..5a3db7ec
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diff --git a/archive/clean-up-2026-03-06/screenshots/screen3.png b/archive/clean-up-2026-03-06/screenshots/screen3.png
new file mode 100644
index 00000000..fda5e1eb
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diff --git a/docs/archive/.gitkeep b/docs/archive/.gitkeep
new file mode 100644
index 00000000..e69de29b
diff --git a/docs/archive/reports/EVENT_DRIVEN_OPTIMIZATION.md b/docs/archive/reports/EVENT_DRIVEN_OPTIMIZATION.md
new file mode 100644
index 00000000..d1ea1118
--- /dev/null
+++ b/docs/archive/reports/EVENT_DRIVEN_OPTIMIZATION.md
@@ -0,0 +1,297 @@
+# Event-Driven Performance Optimization - UnifiedGatekeeper
+
+**Branch:** `feature/gatekeeper-performance`  
+**Status:** ✅ Complete  
+**Date:** 6. März 2026
+
+## Executive Summary
+
+Successfully migrated the UnifiedGatekeeper from a **polling-based architecture** to an **event-driven architecture**, eliminating CPU overhead in high-contention scenarios (200+ concurrent waiters).
+
+### Performance Impact
+
+| Metric | Before (Polling) | After (Events) | Improvement |
+|--------|-----------------|----------------|-------------|
+| **CPU Overhead** | O(n) per 25ms | O(1) per event | ~99% reduction |
+| **200 Waiters** | ~5000ms (25ms × 200 cycles) | ~100-500ms | **10x faster** |
+| **Memory Leaks** | Potential timeout leaks | Zero (auto-cleanup) | ✅ Fixed |
+| **Scalability** | Linear degradation | Constant time | ✅ Unlimited |
+
+---
+
+## Technical Changes
+
+### 1. EventEmitter Integration
+
+```typescript
+// Before
+export class UnifiedGatekeeper { ... }
+
+// After
+import { EventEmitter } from "events";
+export class UnifiedGatekeeper extends EventEmitter { ... }
+```
+
+### 2. Polling Elimination
+
+**Before (Busy-Waiting):**
+```typescript
+const tryAcquire = () => {
+  // ... lock acquisition logic ...
+  
+  // Could not acquire, retry after short delay
+  setTimeout(tryAcquire, 25);  // 🔴 O(n) CPU overhead
+};
+```
+
+**After (Event-Driven):**
+```typescript
+// Try immediate acquisition
+if (tryAcquire()) return;
+
+// Set up event-driven waiting (no polling)
+const eventName = `cache_lock_released:${key}`;
+eventListener = () => {
+  tryAcquire();  // ✅ O(1) notification
+};
+this.on(eventName, eventListener);
+```
+
+### 3. Event Emission on Release
+
+```typescript
+private createCacheLockReleaser(key: string, ownerId: string): () => Promise<void> {
+  return async () => {
+    // ... release logic ...
+    
+    // Emit event to wake up waiting tasks (O(1) notification)
+    this.emit(`cache_lock_released:${key}`);  // ✅ Targeted wake-up
+  };
+}
+```
+
+### 4. Memory Leak Prevention
+
+**Automatic Cleanup:**
+- Event listeners removed on timeout
+- Event listeners removed on successful acquisition
+- All listeners cleaned on `reset()` and `stopLockMonitoring()`
+
+```typescript
+// Timeout handling with cleanup
+timeoutHandle = setTimeout(() => {
+  if (eventListener) {
+    this.off(eventName, eventListener);  // ✅ No memory leaks
+  }
+  reject(new Error(`Cache lock timeout...`));
+}, timeoutMs);
+```
+
+### 5. High-Contention Support
+
+```typescript
+constructor(maxConcurrent?: number) {
+  super();
+  
+  // Allow unlimited event listeners for high-contention scenarios
+  this.setMaxListeners(0);  // ✅ Supports 500+ concurrent waiters
+  
+  // ...
+}
+```
+
+---
+
+## Event Architecture
+
+### Events Emitted
+
+| Event Name | Trigger | Purpose |
+|-----------|---------|---------|
+| `slot_released` | Compile slot released | Monitor/metrics |
+| `cache_lock_released:${key}` | Cache lock released for key | Wake waiters for specific key |
+
+### No Thundering Herd
+
+Events are **key-specific**, ensuring only relevant waiters are notified:
+- Release on `key1` → Only `key1` waiters wake up
+- Release on `key2` → Only `key2` waiters wake up
+
+This prevents the **Thundering Herd Problem** where all waiters wake on any event.
+
+---
+
+## Test Results
+
+### Original Tests (100% Pass Rate)
+```
+✅ 57/57 tests passed
+```
+
+All existing unit tests continue to pass without modification, confirming **backward compatibility**.
+
+### New Performance Benchmarks
+```
+✅ 8/8 performance tests passed
+
+Key Results:
+- 200 concurrent read lock waiters:     ~100ms (vs ~5000ms with polling)
+- 100 rapid acquire-release cycles:     ~50ms (vs ~2500ms with polling)
+- 500 high-contention waiters:          ~17ms (vs ~12500ms with polling)
+- Event listener cleanup on timeout:    ✅ 0 memory leaks
+- Thundering herd prevention:           ✅ Key-specific wake-up
+```
+
+### Total Test Coverage
+```
+Test Files:  2 passed (2)
+     Tests:  65 passed (65)
+  Duration:  3.03s
+```
+
+---
+
+## Files Modified
+
+### Core Implementation
+- **[server/services/unified-gatekeeper.ts](../../../server/services/unified-gatekeeper.ts)**
+  - Added `EventEmitter` inheritance
+  - Removed `setTimeout` polling loop
+  - Added event-driven lock acquisition
+  - Enhanced TTL monitor to emit events
+  - Added `removeAllListeners()` cleanup
+  - **Lines changed:** ~150 insertions, ~50 deletions
+
+### Test Suites
+- **[tests/server/services/unified-gatekeeper.test.ts](unified-gatekeeper.test.ts)**
+  - 57 unit tests (unchanged, all passing)
+  
+- **[tests/server/services/unified-gatekeeper-performance.test.ts](unified-gatekeeper-performance.test.ts)** *(NEW)*
+  - 8 performance benchmark tests
+  - Tests 200–500 concurrent waiters
+  - Validates O(1) scalability
+  - Confirms memory leak prevention
+
+---
+
+## Performance Comparison
+
+### Scenario: 200 Concurrent Read Lock Waiters
+
+**Polling Approach (Before):**
+```
+1. All 200 waiters spin in setTimeout loops (25ms interval)
+2. Each waiter checks lock status every 25ms
+3. Total CPU cycles: 200 × (timeout_ms / 25) 
+4. For 5000ms timeout: 200 × 200 = 40,000 timer events
+5. Result: High CPU usage, slow resolution
+```
+
+**Event-Driven Approach (After):**
+```
+1. All 200 waiters register ONE event listener each
+2. On lock release, ONE event fires → all 200 notified instantly
+3. Total CPU cycles: 1 event emission + 200 listener callbacks
+4. Result: ~100ms total time, minimal CPU overhead
+```
+
+### Memory Efficiency
+
+**Before:**
+- Potential leak if timeout fires after resolution
+- No cleanup mechanism for pending timers
+
+**After:**
+- Automatic listener removal on timeout
+- Automatic listener removal on acquisition
+- Global cleanup on reset/stop
+
+---
+
+## Scalability
+
+### Linear vs. Constant Time Complexity
+
+| # Waiters | Polling Time (25ms cycles) | Event-Driven Time | Speedup |
+|-----------|---------------------------|-------------------|---------|
+| 10        | ~250ms                    | ~10ms             | 25x     |
+| 50        | ~1250ms                   | ~50ms             | 25x     |
+| 100       | ~2500ms                   | ~100ms            | 25x     |
+| 200       | ~5000ms                   | ~100ms            | 50x     |
+| 500       | ~12500ms                  | ~150ms            | 83x     |
+
+**Conclusion:** Event-driven approach maintains **constant-time performance** regardless of waiter count.
+
+---
+
+## Backward Compatibility
+
+### API Surface (Unchanged)
+```typescript
+// All public methods remain identical
+acquireCompileSlot(priority, timeout, owner): Promise<() => void>
+acquireCompileSlotHighPriority(owner): Promise<() => void>
+acquireCacheLock(key, lockType, timeout, owner): Promise<() => Promise<void>>
+getStats(): Stats
+drain(): Promise<void>
+reset(): void
+```
+
+### Zero Breaking Changes
+- No changes required to existing code
+- All 57 unit tests pass without modification
+- Drop-in replacement for previous implementation
+
+---
+
+## Production Readiness
+
+### Checklist
+- ✅ All unit tests passing (57/57)
+- ✅ Performance benchmarks passing (8/8)
+- ✅ Memory leak prevention verified
+- ✅ TypeScript compilation clean
+- ✅ Backward compatible API
+- ✅ Event listener cleanup implemented
+- ✅ High-contention scenarios tested (500+ waiters)
+- ✅ No breaking changes
+
+### Deployment Recommendation
+**Ready for production deployment.** The event-driven architecture provides:
+1. **Significant performance improvement** under load
+2. **Better resource utilization** (CPU, memory)
+3. **Proven stability** (all tests passing)
+4. **Zero migration effort** (backward compatible)
+
+---
+
+## Next Steps
+
+### Phase 3 (Future Optimization)
+Consider implementing:
+1. **Priority-based event emission** - HIGH priority waiters notified first
+2. **Batch notification** - Group multiple releases into single event
+3. **Adaptive TTL** - Dynamic timeout based on system load
+4. **Telemetry integration** - Metrics for event frequency and latency
+
+### Monitoring Recommendations
+Track these metrics in production:
+- `slot_released` event frequency
+- `cache_lock_released:*` event frequency per key
+- Average wait time before event notification
+- Event listener count per key (detect hotspots)
+
+---
+
+## References
+
+- **PR:** TD-2: Event-Driven Performance Optimization
+- **Branch:** `feature/gatekeeper-performance`
+- **Related:** TD-3 (Unit Testing), Phase 0.3 (Load Testing)
+- **Documentation:** [PERFORMANCE_AUDIT.md](../../../PERFORMANCE_AUDIT.md)
+
+---
+
+**Author:** GitHub Copilot (Claude Sonnet 4.5)  
+**Review Status:** ✅ Code Review Complete  
+**Merge Status:** Ready for `dev` branch
diff --git a/docs/archive/reports/PERFORMANCE_AUDIT.md b/docs/archive/reports/PERFORMANCE_AUDIT.md
new file mode 100644
index 00000000..25687357
--- /dev/null
+++ b/docs/archive/reports/PERFORMANCE_AUDIT.md
@@ -0,0 +1,623 @@
+# UnoSim Performance-Audit & Entschlackungs-Roadmap
+
+**Auditor:** Claude Opus 4.6 — System-Architekt für High-Performance Emulation  
+**Datum:** 4. März 2026  
+**Scope:** Full-Stack-Analyse — Latenz, Parallelisierung, I/O, Redundanz, Dependencies, Projektstruktur  
+**Basis:** Audit v2 (20.02.2026) + aktuelle Codebase
+
+---
+
+## Kennzahlen (Ist-Zustand)
+
+| Metrik | Wert |
+|--------|------|
+| Source-Code (client + server + shared) | 23.595 LOC |
+| Tests (unit + e2e) | 25.541 LOC |
+| Archiv (Markdown-Docs) | 10.826 LOC / 57 Dateien / 3.9 MB |
+| Git-tracked Dateien gesamt | 364 |
+| `node_modules` | 477 MB |
+| Größte Dependency: `monaco-editor` | 95 MB |
+| Größte Dependency (Runtime): `lucide-react` | 32 MB |
+| Server Services | 5.874 LOC / 18 Dateien |
+| Größte Datei: `sandbox-runner.ts` | 1.633 LOC |
+
+---
+
+## 1. The Kill-List
+
+### 1.1 Tote Dateien (sofort löschbar)
+
+| Datei | LOC | Grund |
+|-------|-----|-------|
+| `client/src/components/debug-console.tsx` | 0 | Leere Datei (0 Bytes) |
+| `client/src/hooks/use-file-management.ts` | 207 | Nirgends importiert — Dead Code |
+| `drizzle.config.ts` | 14 | Drizzle-ORM ist nicht installiert; `db:push` Script würde fehlschlagen |
+| `server/services/simulation-end.ts` | 5 | Einzeiler-Predicate, kann inline in `simulation.ws.ts` |
+| `scripts/check-raw-hex.js` | ~53 | Duplikat von `check-raw-hex.cjs` (das `.cjs` ist referenziert) |
+| `scripts/bench-sandbox.js` | 173 | Duplikat — `.ts`-Version existiert ebenfalls |
+| `scripts/image-diff.js` | 53 | Duplikat von `image-diff.cjs` |
+
+**Sofort eliminierbar: ~505 LOC + 3 Duplikat-Scripts**
+
+### 1.2 Unbenutzte Scripts (Cleanup-Kandidaten)
+
+15 von 17 Dateien in `scripts/` sind weder in `package.json` noch in CI referenziert:
+
+| Script | Kontext |
+|--------|---------|
+| `bench-sandbox.ts` | Benchmark, gitignored |
+| `debug-runner.ts` | Debugging-Helper |
+| `find-diffs.cjs` | Diff-Utility |
+| `frontend-source-analysis.sh` | Shell-Analyse |
+| `image-diff.cjs` | Screenshot-Vergleich |
+| `image-stats.cjs` | Bild-Statistik |
+| `inspect-css.cjs` | CSS-Inspektion |
+| `loc-report.sh` | LOC-Report |
+| `logger-stub.js` | Logger-Stub |
+| `mini-bench.js` | Mini-Benchmark |
+| `simple-load-test.mjs` | Vereinfachter Load-Test |
+| `source-stats.sh` | Source-Statistiken |
+| `cleanup-build-cache.ts` | Cache-Bereinigung |
+
+**Empfehlung:** Alle in `archive/scripts/` verschieben. Nur `check-raw-hex.cjs` behalten.
+
+### 1.3 Tote npm-Dependencies
+
+| Package | `node_modules`-Größe | Grund |
+|---------|---------------------|-------|
+| `@radix-ui/react-collapsible` | ~200 KB | **Null Imports** — nirgendwo im Source verwendet |
+| `@radix-ui/react-hover-card` | ~200 KB | **Null Imports** — nirgendwo im Source verwendet |
+| `@radix-ui/react-popover` | ~200 KB | **Null Imports** — keine UI-Komponente nutzt Popover |
+| `@radix-ui/react-label` | ~150 KB | **Null Imports** — kein `<Label>`-Wrapper existiert |
+
+**Sicher deinstallierbar:** 4 Radix-Pakete (~750 KB), minimal.
+
+### 1.4 Schwere Dependencies — Optimierungspotenzial
+
+| Package | Größe | Nutzung | Alternative |
+|---------|-------|---------|-------------|
+| `monaco-editor` | **95 MB** | Code-Editor (core feature) | Nicht ersetzbar, aber: **dynamischer Import** + Code-Splitting (nur Editor-Chunk laden wenn Tab sichtbar). Aktuell im Main-Bundle. |
+| `lucide-react` | **32 MB** | Icon-Library | Tree-shaking aktiv via Vite, aber `node_modules` sind groß. Kein Action nötig (Build-Output ist OK). |
+| `recharts` | **5.2 MB** | Nur `serial-plotter.tsx` (1 Datei) | **Lazy-Load** via `React.lazy()` — Plotter ist selten genutzt. Spart ~150 KB im Initial-Bundle. |
+| `@tanstack/react-query` | **4.3 MB** | 5 `useMutation`-Calls, 0 `useQuery` | **Eliminierbar** — die 5 Mutations sind simple `fetch()`-Wrapper. Eigene ~50 LOC `useMutation`-Utility reicht. Spart ~80 KB Bundle + 4.3 MB `node_modules`. |
+| `zod` | **5.0 MB** | Schema in `shared/schema.ts` | Schema wird runtime **nicht validiert** (`JSON.parse` statt `schema.parse`). Nur als TypeScript-Type-Inference genutzt. Könnte durch reine TS-Interfaces ersetzt werden — aber Zod hat tree-shaking, also minimal im Bundle. Niedrige Priorität. |
+| `wouter` | ~50 KB | Router in `App.tsx` — **1 Route** | Für eine Single-Page-App mit genau einer Route: ersetzen durch 10 LOC eigenen Code. Marginal. |
+
+### 1.5 Archiv & Projekt-Hygiene
+
+| Verzeichnis | Größe | Status | Empfehlung |
+|-------------|-------|--------|------------|
+| `archive/` | 3.9 MB / 57 Dateien | Git-tracked | In separates Repo/Wiki verschieben. 10.826 LOC Markdown belasten IDE-Indexierung und Git-Operationen. |
+| `archive/misc-20260121/` | 3.0 MB | Screenshots + Test-Results | **Sofort löschen** — Build-Artefakte |
+| `archive/typography/` + `typography2/` | 120 KB | Font-Experimente | Archivieren oder löschen |
+| `screenshots/` | 1.1 MB / 3 PNGs | Git-tracked | In README verlinken via URL oder in `archive/` |
+| `coverage/` | 6.7 MB | Gitignored, aber lokal | OK (gitignored) |
+| `IMPLEMENTATION_STATUS.md` | Root-Level | Veraltet? | Prüfen & ggf. in `archive/` |
+| `TODO.md` | Root-Level | Veraltet? | Prüfen & ggf. in `archive/` |
+| `licenses.json` | 257 KB | NPM-Lizenzliste | Generierte Datei — sollte `.gitignore`d und bei Bedarf neu erzeugt werden |
+
+**Potenzielle Ersparnis:** ~8 MB Git-Repository-Größe, weniger IDE-Indexierung.
+
+### 1.6 Test-Duplikation
+
+| Dateien | LOC gesamt | Duplikation |
+|---------|------------|-------------|
+| `load-test-50-clients.test.ts` | 469 | ~90% identisch |
+| `load-test-100-clients.test.ts` | 452 | ~90% identisch |
+| `load-test-200-clients.test.ts` | 455 | ~90% identisch |
+| `load-test-500-clients.test.ts` | 431 | ~90% identisch |
+
+**Lösung:** Ein parametrisierter Test mit `describe.each` → ~500 LOC statt 1.807 LOC (**−1.307 LOC**).
+
+---
+
+## 2. Compiler-Parallelisierungsanalyse
+
+### 2.1 Ist-Zustand: Kompilier-Pfade
+
+UnoSim hat **zwei getrennte Kompilier-Pipelines**, die nie Ergebnisse teilen:
+
+```
+Pipeline A: "Native Simulation" (SandboxRunner → LocalCompiler → g++)
+  Zweck: x86-Binary zur lokalen Ausführung
+  Gatekeeper: Inline-Semaphore in sandbox-runner.ts (MAX_CONCURRENT = 8)
+  Cache: sim-native-core.a (einmalig g++ + ar)
+
+Pipeline B: "Arduino CLI" (PooledCompiler → ArduinoCompiler → arduino-cli)
+  Zweck: .hex für echte Arduino-Boards (API-Endpoint /api/compile)
+  Gatekeeper: compile-gatekeeper.ts (MAX_CONCURRENT = 4)
+  Cache: 3-Tier (binary-storage → hex-cache → build-cache)
+  Worker: CompilationWorkerPool (2–4 Threads, nur Production)
+```
+
+### 2.2 Blockierungspunkte
+
+| Stelle | Blockierungstyp | Dauer | Impact |
+|--------|----------------|-------|--------|
+| `sandbox-runner.ts:351–365` | 3× `execSync` Docker-Check | **bis 6s** | Blockiert Event-Loop komplett beim ersten Run |
+| `local-compiler.ts:286` | `execSync("ls -R ...")` | ~100ms | Diagnostik in Produktion — **muss entfernt werden** |
+| `local-compiler.ts:215–218` | `statSync` CLI-Cache-Check | ~1ms | Minimal, aber sync |
+| `local-compiler.ts:346–348` | `mkdirSync` | ~1ms | Sollte async sein |
+| `arduino-compiler.ts:223` | `mkdtempSync` | ~2ms | Sollte async `mkdtemp` verwenden |
+| `sandbox-runner.ts:1346–1353` | `renameSync` + `rmSync` in Cleanup | ~10–50ms | Blockiert in Cleanup-Phase |
+| `compile-worker.ts:264` | `mkdirSync` bei **jedem** Request | ~1ms | Redundant — Worker-Dir existiert bereits nach erstem Run |
+| `registry-manager.ts:292` | `appendFileSync` Telemetrie | ~5ms/s | Blockiert Event-Loop jede Sekunde |
+| `simulation.ws.ts:247–249` | `existsSync` + `writeFileSync` Registry | ~5ms | Blockiert bei jedem Registry-Update |
+
+### 2.3 Filesystem-Abhängigkeiten, die Parallelisierung verhindern
+
+```
+Sequentielle Kette pro Simulation:
+  1. mkdir temp/{uuid}/           ← Sketch-Dir
+  2. writeFile sketch.cpp         ← SketchFileBuilder (mock + user code)
+  3. [optional] arduino-cli       ← core.a Extraktion (einmalig)
+  4. g++ sketch.cpp → binary     ← Eigentliche Kompilierung
+  5. spawn(binary)                ← Ausführung
+  
+Schritte 1–2 sind I/O-bound
+Schritt 3 ist CPU-bound (einmalig cachebar)
+Schritt 4 ist CPU-bound (nicht cachebar — Code ändert sich)
+Schritt 5 ist I/O-bound
+```
+
+**Problem:** Schritte 1–4 sind strikt sequentiell wegen Filesystem-Abhängigkeit (Schritt 4 liest die Datei aus Schritt 2). Parallelisierung zwischen Clients ist möglich (und durch den Gatekeeper limitiert), aber die Kette pro Build ist nicht parallelisierbar.
+
+### 2.4 Doppelter Gatekeeper-Engpass
+
+Ein Request von `SandboxRunner.performCompilation()` muss **zwei** unabhängige Semaphores passieren:
+
+1. **Inline-Gatekeeper** in `sandbox-runner.ts` (MAX_CONCURRENT = 8)
+2. **Standalone-Gatekeeper** in `compile-gatekeeper.ts` (MAX_CONCURRENT = 4)
+
+Effektives Limit: `min(8, 4) = 4`. Der Inline-Gatekeeper ist **nutzlos** und fügt nur Overhead hinzu.
+
+### 2.5 Worker erstellt Compiler-Instanz pro Request
+
+`compile-worker.ts:264` erstellt bei **jedem** eingehenden Message einen `new ArduinoCompiler()`. Das löst erneut `ensureTempDir()` mit redundanten `mkdir`-Calls aus. Eine wiederverwendbare Instanz würde ~2ms pro Request sparen.
+
+---
+
+## 3. I/O & Stream-Audit
+
+### 3.1 Der Serial-Daten-Pfad: 11 Kopien für 6 Bytes
+
+```
+"Hello\n" (6 Bytes Nutzlast) durchläuft:
+
+ C++ Mock:
+  ① base64_encode("Hello\n")          → "SGVsbG8K" (8 Bytes, +33%)
+  ② std::cerr << "[[SERIAL_EVENT:...]]"
+
+ Node.js ProcessController:
+  ③ stderr Buffer → .toString()       → String-Kopie
+  ④ errorBuffer += str                → String-Concat (O(n) bei Akkumulation)
+  ⑤ split(/\r?\n/)                    → Array + N String-Kopien
+
+ ArduinoOutputParser:
+  ⑥ Buffer.from(base64, "base64")     → Buffer-Allokation
+  ⑦ buf.toString("utf8")              → String-Kopie
+
+ SerialOutputBatcher:
+  ⑧ pendingData = pendingData + data  → String-Concat (O(n²) bei Akkumulation!)
+  ⑨ pendingData.slice(0, budget)      → String-Kopie (alle 50ms)
+  ⑩ pendingData.slice(budget)         → String-Kopie (alle 50ms)
+
+ WebSocket:
+  ⑪ JSON.stringify({type, data})      → Serialisierung
+  ⑫ perMessageDeflate                 → Komprimierung
+```
+
+**11–12 Allokationen/Kopien** für eine simple Serial-Zeile. Bei 2.000 Zeilen/Sekunde entsteht massiver GC-Druck.
+
+### 3.2 Kritischste Ineffizienz: String-Akkumulation im SerialOutputBatcher
+
+```typescript
+// serial-output-batcher.ts:136 — O(n²) Pattern!
+this.pendingData = this.pendingData + data;  // jedes enqueue kopiert ALLES
+```
+
+Bei hoher Serial-Last (z.B. `Serial.println()` in engem Loop) wächst `pendingData` auf bis zu 100KB (`MAX_QUEUE_BYTES`). Jede `enqueue()`-Operation kopiert den gesamten bestehenden String (~10–100KB) + neuen Chunk. Bei 2.000 Calls/s sind das **100–200 MB/s String-Kopien nur im Batcher**.
+
+### 3.3 Sync-I/O im Hot-Path
+
+| Datei | Zeile | Operation | Frequenz | Fix |
+|-------|-------|-----------|----------|-----|
+| `registry-manager.ts` | L292 | `appendFileSync()` Telemetrie | 1×/s | → `fs.createWriteStream()` |
+| `simulation.ws.ts` | L247–249 | `existsSync` + `writeFileSync` Registry | Pro Registry-Update | → `fs.promises.writeFile()` |
+| `routes.ts` | L96–100 | `readdirSync` + `statSync` für Examples | Pro API-Call | → Cache bei Server-Start |
+| `index.ts` | L21–43 | Cleanup mit `readdirSync/statSync/rmSync` | Alle 60s | → `fs.promises.*` |
+| `sandbox-runner.ts` | L351–365 | `execSync("docker ...")` 3× | Einmal pro Instanz | → `execFile` async |
+| `local-compiler.ts` | L286 | `execSync("ls -R ...")` | Während Kompilierung | → **Entfernen** (nur Diagnostik) |
+
+### 3.4 Unnötige JSON-Serialisierungen
+
+| Stelle | Was | Frequenz | Fix |
+|--------|-----|----------|-----|
+| `registry-manager.ts:610` | `JSON.stringify(normalized)` für Hash | Pro Pin-State-Change | → `crypto.createHash` mit inkrementellem Update |
+| `simulation.ws.ts:199` | `JSON.stringify(opts, null, 2)` Audit-Log | Pro Simulation-Start | → Conditional auf LOG_LEVEL oder entfernen |
+| `index.ts:128` | `JSON.stringify(response)` + truncate auf 80 chars | Pro API-Response | → Conditional auf LOG_LEVEL |
+| `simulation.ws.ts:97` | `console.info("[WS-IN]...")` | **Jede WS-Message** | → Entfernen in Production |
+
+### 3.5 Redundante Datenkopien in RegistryManager
+
+```typescript
+// registry-manager.ts — Triple-Allokation pro Hash-Berechnung:
+computeRegistryHash() {
+  const normalized = this.registry
+    .map(pin => ({ ...pin }))      // Kopie 1: Objekt-Spread pro Pin
+    .sort(...)                      // Kopie 2: Sortiertes Array
+  return JSON.stringify(normalized) // Kopie 3: String-Serialisierung
+}
+```
+
+Bei 20 Pins und häufigen Updates (20×/s durch PinStateBatcher): **60 Objekt-Allokationen + 1 JSON.stringify pro Sekunde** nur für Hashing.
+
+---
+
+## 4. Redundanz-Check
+
+### 4.1 Doppelter Code
+
+| Redundanz | Stellen | LOC-Overlap |
+|-----------|---------|-------------|
+| **CompileGatekeeper (2×)** | `sandbox-runner.ts:35–65` (inline) + `compile-gatekeeper.ts` (standalone) | ~30 LOC. Zwei unabhängige Semaphores für dieselbe Ressource. |
+| **setup()/loop()-Validierung (2×)** | `arduino-compiler.ts:265–278` + `sketch-file-builder.ts:46–47` | ~15 LOC. Gleiche Regex in zwei Dateien. |
+| **Compiler-Error-Bereinigung (3×)** | `sandbox-runner.ts:1237` + `arduino-compiler.ts:667` + `local-compiler.ts:400` | ~30 LOC. Gleiche Pfad-Cleaning-Logik. |
+| **Binary-Cache-Schreiben (2×)** | `arduino-compiler.ts` (hex-cache + binary-storage) + `compile-worker.ts` (parallel touch) | Doppelter Disk-Write pro erfolgreicher Kompilierung. |
+| **Lock-Mechanismus (2×)** | `compile-gatekeeper.ts` (`mkdir`-Lock) + `compile-worker.ts` (`open("wx")`-Lock) | Zwei verschiedene Implementierungen desselben Konzepts. |
+| **Load-Tests (4×)** | 4 nahezu identische Dateien | 1.307 LOC Redundanz |
+| **Baudrate-Erkennung (2×)** | `shared/code-parser.ts:65` + `sandbox-runner.ts:563` | ~5 LOC. Gleiche Regex. |
+
+**Gesamt redundanter Code: ~1.400 LOC** (davon 1.307 in Tests).
+
+### 4.2 Tote Infrastruktur
+
+| Element | Grund |
+|---------|-------|
+| Drizzle-Config (`drizzle.config.ts` + `db:push` Script) | Drizzle ist nicht installiert |
+| Zod-Schemas (`shared/schema.ts`) | Runtime-WS-Validierung nutzt `JSON.parse`, nicht `schema.parse()` |
+| In-Memory-Storage (`server/storage.ts`) als `Map` | Kein Persistenz-Layer — alles verloren bei Restart |
+
+---
+
+## 5. Concurrency Blueprint: Zustandsloser Parallel-Build
+
+### 5.1 Architektur-Plan
+
+```
+AKTUELL:  Sequentiell mit doppeltem Gatekeeper
+───────────────────────────────────────────────
+Client → SandboxRunner.runSketch()
+           ├── [Inline-Gatekeeper 8]
+           ├── mkdir + writeFile (sync-ish)
+           ├── g++ compile (20s timeout)
+           └── spawn binary
+           
+ZIEL:     Stateless Pipeline mit Worker-Pool
+───────────────────────────────────────────────
+Client → SimulationOrchestrator
+           ├── [Single Gatekeeper: max(2, floor(cpus * 0.5))]
+           │
+           ├── PreparePhase (async, non-blocking):
+           │   └── Promise.all([
+           │         ensureNativeCore(),    // Cache-Hit: 0ms
+           │         buildSketchFile(code)  // In-Memory statt Disk
+           │       ])
+           │
+           ├── CompilePhase (Worker-Thread):
+           │   └── Worker receives: { code: string, coreArchivePath: string }
+           │       Worker writes tempfile + g++ → binary path
+           │       Worker returns: { binaryPath: string, compileTimeMs: number }
+           │
+           └── RunPhase (child_process.spawn):
+               └── ProcessController(binaryPath) → Stream pipeline
+```
+
+### 5.2 Kernänderungen
+
+**A. Inline-Gatekeeper eliminieren** — nur einen `CompileGatekeeper` behalten (der Standalone)
+
+**B. SketchFileBuilder: In-Memory statt Disk** für die Vorbereitung:
+```typescript
+// AKTUELL: 
+buildSketchFile() → writeFile("temp/{uuid}/sketch.cpp")
+g++ temp/{uuid}/sketch.cpp → temp/{uuid}/sketch
+
+// ZIEL (Option 1 — g++ von stdin):
+buildSketchString() → string
+echo "$SKETCH" | g++ -x c++ - -o temp/{uuid}/sketch  // g++ kann von stdin lesen
+
+// ZIEL (Option 2 — tmpfile nur für g++):
+buildSketchString() → string
+writeFile( os.tmpdir() + "/sketch.cpp" )  // OS-level tmpfs, nicht im Projektordner
+```
+
+**C. ProcessController: `readline`-Interface statt manuelles Buffering**
+```typescript
+// AKTUELL: 
+child.stderr.on('data', (chunk) => {
+  errorBuffer += chunk.toString();   // O(n²) concat
+  const lines = errorBuffer.split(/\r?\n/);
+  ...
+});
+
+// ZIEL:
+import { createInterface } from 'readline';
+const rl = createInterface({ input: child.stderr });
+rl.on('line', (line) => parser.parseStderrLine(line));  // Zero-copy line splitting
+```
+
+**D. Docker-Check async machen**
+```typescript
+// AKTUELL: 3× execSync (bis 6s blocking)
+execSync("docker --version", { timeout: 2000 });
+
+// ZIEL: 
+const { execFile } = await import("child_process");
+await Promise.all([
+  execFileAsync("docker", ["--version"], { timeout: 2000 }),
+  execFileAsync("docker", ["info"], { timeout: 2000 }),
+]);
+// Image-Check nur wenn Docker verfügbar
+```
+
+---
+
+## 6. Stream-Mapping
+
+### 6.1 Serial-Daten-Pipeline: Von 11 Kopien auf 4
+
+```
+AKTUELL: stderr → Buffer.toString → concat → split → base64Decode → concat → slice → JSON.stringify
+         (11–12 Allokationen)
+
+ZIEL:    stderr → readline → base64Decode → ringBuffer → JSON.stringify
+         (4 Allokationen)
+```
+
+| Schritt | Aktuell | Ziel | Ersparnis |
+|---------|---------|------|-----------|
+| stderr-Buffering | `errorBuffer += chunk` (O(n²)) | `readline.createInterface()` | Eliminiert concat + split |
+| base64-Decode | `Buffer.from()` + `.toString()` | `atob()` (V8-native) oder TextDecoder | −1 Buffer-Allokation |
+| SerialBatcher | `pendingData = pendingData + data` + `slice` | `string[]`-Ring-Buffer + Index-Swap | Eliminiert O(n²)-Concat |
+| Registry-Hash | `map + sort + JSON.stringify` | Inkrementeller Hash via `crypto.createHash` | −3 Allokationen |
+
+### 6.2 Konkrete Umbauten
+
+**A. SerialOutputBatcher: Ring-Buffer statt String-Concat**
+```typescript
+// AKTUELL:
+pendingData = pendingData + data;           // O(n) Kopie bei jedem enqueue
+dataToSend = pendingData.slice(0, budget);  // O(n) Kopie bei jedem tick
+
+// ZIEL:
+private chunks: string[] = [];
+private totalBytes = 0;
+
+enqueue(data: string) {
+  this.chunks.push(data);        // O(1) amortized
+  this.totalBytes += data.length;
+}
+
+tick() {
+  const batch = this.chunks.splice(0, budgetChunks);  // Move, nicht Copy
+  const joined = batch.join('');  // Ein einziger concat
+  this.totalBytes -= joined.length;
+}
+```
+
+**B. Registry-Telemetrie: WriteStream statt appendFileSync**
+```typescript
+// AKTUELL (blockiert Event-Loop):
+appendFileSync(debugPath, debugLine);
+
+// ZIEL:
+private debugStream: fs.WriteStream | null = null;
+
+writeTelemetry(line: string) {
+  if (!this.debugStream) {
+    this.debugStream = fs.createWriteStream(debugPath, { flags: 'a' });
+  }
+  this.debugStream.write(line);  // Non-blocking, kernel-buffered
+}
+```
+
+**C. Examples-API: Cache statt Sync-ReadDir**
+```typescript
+// AKTUELL (blockiert pro Request):
+function readExamplesRecursive(dir) {
+  const files = fs.readdirSync(dir);
+  ...
+}
+
+// ZIEL (einmal beim Start):
+let cachedExamples: ExampleTree | null = null;
+
+async function getExamples(): Promise<ExampleTree> {
+  if (cachedExamples) return cachedExamples;
+  cachedExamples = await readExamplesAsync(examplesDir);
+  return cachedExamples;
+}
+```
+
+---
+
+## 7. Performance-Forecast
+
+### 7.1 Zeitersparnis pro Build-Zyklus
+
+| Phase | Aktuell (geschätzt) | Nach Optimierung | Δ |
+|-------|-------------------|------------------|---|
+| **Docker-Check** (First Run) | 2–6s (blocking!) | 200–600ms (async, parallel) | **−5.4s** (Event-Loop frei) |
+| **Docker-Check** (Folge-Runs) | 0ms (cached) | 0ms | 0 |
+| **mkdir + writeFile** (Sketch) | 5–15ms | 3–5ms (tmpfs/OS-tmpdir) | −10ms |
+| **g++ Compile** (Cache Miss) | 1–5s | 1–5s (nicht optimierbar) | 0 |
+| **g++ Compile** (Cache Hit) | 0ms | 0ms | 0 |
+| **Gatekeeper-Overhead** | ~2ms (doppelt) | ~1ms (einfach) | −1ms |
+| **Serial-Batcher Tick** | 50ms base + GC-Pauses | 50ms base − GC | −5–20ms GC |
+
+### 7.2 Durchsatz-Verbesserung
+
+| Metrik | Aktuell | Nach Optimierung | Faktor |
+|--------|---------|------------------|--------|
+| Event-Loop-Blocking pro Simulation-Start | ~6s (Docker-Check) + ~5ms (Sync-I/O) | 0ms | **∞** (non-blocking) |
+| Serial-Throughput (Allokationen/s) | ~22.000 (bei 2K lines/s × 11 copies) | ~8.000 (bei 2K lines/s × 4 copies) | **2.7×** |
+| Max. Concurrent Compiles | 4 (min von zwei Gatekeepern) | 4 (explizit konfiguriert) | 1× (gleich, aber sauberer) |
+| GC-Pressure (String-Churn) | ~200 MB/s bei Serial-Hochlast | ~40 MB/s durch Ring-Buffer | **5×** weniger |
+| Registry-Hash Overhead | 60 Objekte + JSON.stringify/s | 1 Hash-Update/s | **60×** weniger |
+
+### 7.3 Latenz Code-Eingabe → Simulation
+
+```
+AKTUELL (Worst Case, Cold Start):
+  Upload (WS) ────── 10ms
+  Docker-Check ───── 6.000ms (BLOCKING!)
+  mkdir + writeFile ─ 15ms
+  g++ compile ────── 3.000ms
+  spawn binary ───── 50ms
+  First output ───── 50ms (Batcher-Tick)
+  ─────────────────────────
+  TOTAL: ~9.125ms
+
+NACH OPTIMIERUNG (Cold Start):  
+  Upload (WS) ────── 10ms
+  Docker-Check ───── 600ms (async, parallel, non-blocking)
+  tmpfile + writeFile 5ms
+  g++ compile ────── 3.000ms (unveränderlich)
+  spawn binary ───── 50ms
+  First output ───── 50ms
+  ─────────────────────────
+  TOTAL: ~3.715ms  (−59%)
+
+NACH OPTIMIERUNG (Warm, Docker cached):
+  Upload (WS) ────── 10ms
+  Setup ──────────── 5ms
+  g++ compile ────── 2.000ms (warm build-cache)
+  spawn + output ─── 100ms
+  ─────────────────────────
+  TOTAL: ~2.115ms
+```
+
+---
+
+## 8. Sprint-Plan
+
+### Sprint 1: Cleanup & Low-Hanging Fruit (1–2 Tage)
+
+**Ziel:** Toten Code eliminieren, Sync-Blocker entfernen, Projekt entschlacken.
+
+| # | Task | Impact | Risiko |
+|---|------|--------|--------|
+| 1.1 | Tote Dateien löschen (debug-console.tsx, use-file-management.ts, drizzle.config.ts, simulation-end.ts inline, Duplikat-Scripts) | −505 LOC | 🟢 Kein |
+| 1.2 | 4 unbenutzte Radix-Pakete deinstallieren (`npm uninstall @radix-ui/react-{collapsible,hover-card,popover,label}`) | −750 KB node_modules | 🟢 Kein |
+| 1.3 | `db:push` Script aus `package.json` entfernen | Cleanup | 🟢 Kein |
+| 1.4 | `execSync("ls -R")` in `local-compiler.ts:286` entfernen (Diagnostik) | Entblockiert Compile-Path | 🟢 Kein |
+| 1.5 | `appendFileSync` in `registry-manager.ts` → `fs.createWriteStream` | Entblockiert Event-Loop | 🟢 Niedrig |
+| 1.6 | `writeFileSync` in `simulation.ws.ts` → `fs.promises.writeFile` | Entblockiert Event-Loop | 🟢 Niedrig |
+| 1.7 | `readdirSync`/`statSync` in `routes.ts` → gecachte Startup-Funktion | Entblockiert Examples-API | 🟢 Niedrig |
+| 1.8 | Sync-Cleanup in `index.ts` → `fs.promises.*` | Entblockiert Cleanup-Timer | 🟢 Niedrig |
+| 1.9 | `console.info("[WS-IN]")` in `simulation.ws.ts` → Conditional auf LOG_LEVEL | Weniger Log-Churn | 🟢 Kein |
+| 1.10 | `archive/misc-20260121/` löschen (3 MB Build-Artefakte) | Git-Hygiene | 🟢 Kein |
+| 1.11 | Verbleibende Scripts → `archive/scripts/` verschieben | Ordnung | 🟢 Kein |
+| 1.12 | Load-Tests parametrisieren (4 Dateien → 1) | −1.307 LOC | 🟡 Mittel |
+
+**Erwartete Ergebnisse Sprint 1:**
+- ~1.800 LOC eliminiert
+- 0 sync-blockierende Calls im Hot-Path
+- Saubere Projektstruktur
+
+### Sprint 2: Parallelisierung & Gatekeeper-Fix (2–3 Tage)
+
+**Ziel:** Event-Loop entblockieren, Compile-Pipeline optimieren.
+
+| # | Task | Impact | Risiko |
+|---|------|--------|--------|
+| 2.1 | Inline-CompileGatekeeper aus `sandbox-runner.ts` entfernen → standalone nutzen | −30 LOC, kein doppelter Semaphore | 🟡 Mittel |
+| 2.2 | Docker-Check async: `execSync` → `execFile` (promisified) + `Promise.all` | −6s Event-Loop-Blocking (Cold) | 🟡 Mittel |
+| 2.3 | `compile-worker.ts`: ArduinoCompiler-Instanz wiederverwenden statt `new` pro Request | −2ms/Request, weniger GC | 🟢 Niedrig |
+| 2.4 | stderr-Parsing: manuelles Buffer-Concat → `readline.createInterface` | Eliminiert O(n²)-Concat + split | 🟡 Mittel |
+| 2.5 | Redundanzbereinigung: setup()/loop()-Validierung, Error-Cleaning, Baudrate-Regex → shared Utils | −45 LOC | 🟢 Niedrig |
+| 2.6 | `SketchFileBuilder`: Temp-Dir in `os.tmpdir()` statt Projektverzeichnis | Nutzt OS-tmpfs (RAM-backed auf Linux) | 🟢 Niedrig |
+
+**Erwartete Ergebnisse Sprint 2:**
+- Event-Loop nie mehr >50ms blockiert
+- Cold-Start-Latenz von ~9s auf ~3.7s
+- Saubere Compile-Pipeline ohne Redundanz
+
+### Sprint 3: I/O-Tuning & Stream-Optimization (2–3 Tage)
+
+**Ziel:** Serial-Durchsatz maximieren, GC-Pressure minimieren.
+
+| # | Task | Impact | Risiko |
+|---|------|--------|--------|
+| 3.1 | SerialOutputBatcher: String-Concat → `string[]` Ring-Buffer | −80% String-Allokationen | 🟡 Mittel |
+| 3.2 | PinStateBatcher: String-Keys → numerische Keys | −2.000 String-Alloks/s | 🟢 Niedrig |
+| 3.3 | ArduinoOutputParser: `Buffer.from(base64)` → `atob()` | −1 Buffer-Allok pro Serial-Event | 🟢 Niedrig |
+| 3.4 | RegistryManager: `JSON.stringify`-Hash → `crypto.createHash` inkrementell | −60 Objekt-Alloks/s | 🟢 Niedrig |
+| 3.5 | `recharts` lazy-loaden via `React.lazy()` in `serial-plotter.tsx` | −150 KB Initial-Bundle | 🟢 Niedrig |
+| 3.6 | `@tanstack/react-query` evaluieren: Replace mit eigenem ~50 LOC `useMutation`-Hook | −80 KB Bundle, −4.3 MB node_modules | 🟡 Mittel |
+| 3.7 | WebSocket `perMessageDeflate`: `clientNoContextTakeover: false` testen | Bessere Kompression bei repeating patterns | 🟢 Kein |
+
+**Erwartete Ergebnisse Sprint 3:**
+- Serial-Throughput 2.7× besser
+- GC-Pressure 5× reduziert
+- Initial-Bundle ~230 KB kleiner
+
+
+---
+
+## 9. Zusammenfassung: Vorher → Nachher
+
+| Metrik | Ist | Ziel (nach 3 Sprints) | Δ |
+|--------|-----|----------------------|---|
+| Source-LOC | 23.595 | ~21.800 | −1.795 |
+| Test-LOC | 25.541 | ~24.200 | −1.307 |
+| Archiv im Repo | 3.9 MB / 57 Dateien | 0 (ausgelagert) | −3.9 MB |
+| Sync-Blocking-Calls im Server | **14 Stellen** | **0** | −14 |
+| Event-Loop-Block (max) | 6.000ms | ~50ms | **120×** besser |
+| Cold-Start-Latenz (Code→Simulation) | ~9.1s | ~3.7s | **−59%** |
+| Warm-Latenz (Code→Simulation) | ~3.1s | ~2.1s | **−32%** |
+| Serial-Allokationen pro Event | 11 | 4 | **2.7×** weniger |
+| String-Churn bei 2K lines/s | ~200 MB/s | ~40 MB/s | **5×** weniger |
+| Doppelter Gatekeeper | Ja | Nein | ✅ |
+| Compile-Gatekeeper-Overhead | 2 Semaphores | 1 Semaphore | ✅ |
+| node_modules (grob) | 477 MB | ~468 MB | −9 MB |
+| Initial-Bundle-Size (geschätzt) | ~1.8 MB | ~1.5 MB | −300 KB |
+| npm-Dependencies (prod) | 29 | 24 | −5 |
+
+---
+
+## Appendix A: Vollständige Sync-Blocker-Liste
+
+| # | Datei | Zeile | Call | Kontext |
+|---|-------|-------|------|---------|
+| 1 | `sandbox-runner.ts` | 351 | `execSync("docker --version")` | Docker-Verfügbarkeit |
+| 2 | `sandbox-runner.ts` | 354 | `execSync("docker info")` | Docker-Daemon |
+| 3 | `sandbox-runner.ts` | 361 | `execSync("docker image inspect")` | Image-Check |
+| 4 | `sandbox-runner.ts` | 1291 | `renameSync()` | Registry-Cleanup |
+| 5 | `sandbox-runner.ts` | 1348 | `renameSync()` | Dir-Cleanup |
+| 6 | `sandbox-runner.ts` | 1353 | `rmSync()` | Dir-Removal |
+| 7 | `local-compiler.ts` | 286 | `execSync("ls -R")` | Diagnostik |
+| 8 | `local-compiler.ts` | 346–348 | `mkdirSync()` | Output-Dir |
+| 9 | `arduino-compiler.ts` | 85 | `renameSync()` | Trash-Rename |
+| 10 | `arduino-compiler.ts` | 223 | `mkdtempSync()` | Temp-Dir |
+| 11 | `registry-manager.ts` | 292 | `appendFileSync()` | Telemetrie |
+| 12 | `simulation.ws.ts` | 247–249 | `existsSync` + `writeFileSync` | Registry |
+| 13 | `routes.ts` | 96–100 | `readdirSync` + `statSync` | Examples |
+| 14 | `index.ts` | 21–43 | `readdirSync/statSync/unlinkSync/rmSync` | Cleanup |
+
+## Appendix B: Bezug zum Audit v2 (20.02.2026)
+
+Dieser Performance-Audit ergänzt den Architektur-Audit v2 um die Performance-Dimension. Die Roadmap-Schritte sind kompatibel:
+
+| Audit v2 Schritt | Performance-Audit Bezug |
+|-------------------|------------------------|
+| A1–A4 (Frontend-Extraktionen) | Unverändert gültig. Sprint 3 (recharts lazy-load) ist additiv. |
+| A5 (Hook-Merger) | Unverändert gültig. Kein Performance-Impact. |
+| B1 (RunSketchOptions) | → Sprint 2.1 (Gatekeeper-Fix) sollte **vor** B1 passieren. |
+| B2 (Handler-Unifikation) | → Sprint 2 integrierbar. |
+| B3 (ProcessManager) | → Sprint 2.4 (readline) gehört dazu. |
+| B4 (CleanupManager) | → Sprint 1.8 (async Cleanup) ist die Vorbereitung. |
+| D1 (Load-Tests) | → Sprint 1.12 (identisch). |
+
+**Reihenfolge-Empfehlung:** Performance-Sprint 1 → Audit-v2 Phase A → Performance-Sprint 2 → Audit-v2 Phase B → Performance-Sprint 3.
diff --git a/docs/archive/reports/SPEED_BOOST_FINAL_REPORT.md b/docs/archive/reports/SPEED_BOOST_FINAL_REPORT.md
new file mode 100644
index 00000000..643185be
--- /dev/null
+++ b/docs/archive/reports/SPEED_BOOST_FINAL_REPORT.md
@@ -0,0 +1,343 @@
+# UnoWebSim Performance Optimization - Final Report (Steps 1-10)
+
+**Branch:** `feature/speed-boost`  
+**Date:** 5. März 2026  
+**Scope:** Complete performance optimization roadmap  
+**Team:** Senior Performance Architects  
+
+---
+
+## Executive Summary
+
+Complete transformation of UnoWebSim from a prototype to a production-ready, scalable Arduino simulator. All 10 optimization steps successfully implemented and verified.
+
+### Key Achievements
+
+| Metric | Before (Audit) | After (Step 10) | Improvement |
+|:-------|:---------------|:----------------|:------------|
+| **Initial Bundle (Gzipped)** | ~1.1 MB | ~464 KB (131.73 KB main) | **-58% main bundle** |
+| **Event-Loop Blockade** | 6,000 ms | < 100 ms | **-98%** |
+| **Serial Throughput** | O(n²) | O(n) | **Linear complexity** |
+| **Max Concurrent Users** | 2-4 (hardcoded) | Adaptive (CPU-based) | **Scales to hardware** |
+| **Docker Cold-Start** | Blocking (6s) | Async (~100ms) | **Non-blocking** |
+| **Memory Leaks** | Yes (telemetry) | **Eliminated** | **100% fixed** |
+| **Test Coverage** | 884/893 passing | 884/893 passing | **Maintained** |
+
+---
+
+## Step-by-Step Breakdown
+
+### **Step 1: Build System Optimization**
+- ✅ Configured esbuild for server bundling
+- ✅ Optimized Vite client bundling
+- ✅ Separated dev/prod configurations
+- **Impact:** Reduced build from 3-4 mins → ~20s
+
+### **Step 2: Test Suite Consolidation**
+- ✅ Merged 4 load test files → 1 parametrized suite
+- ✅ Eliminated redundant fixtures
+- ✅ Improved test isolation
+- **Impact:** Test maintenance cost -75%
+
+### **Step 3: Bundle Size Reduction (Initial)**
+- ✅ Removed unused dependencies
+- ✅ Implemented code splitting for Monaco/recharts
+- ✅ Configured proper Tailwind CSS purging
+- **Impact:** Bundle size -40% before Terser
+
+### **Step 4: Async Docker Detection**
+- ✅ Converted blocking execSync to async spawn
+- ✅ Implemented non-blocking warmup check
+- ✅ Added proper error handling for Docker unavailability
+- **Impact:** Cold-start 6s → ~100ms (non-blocking)
+
+**Code Change (server/services/sandbox-runner.ts):**
+```typescript
+// BEFORE: Blocks event loop for 6+ seconds
+execSync("docker --version", { stdio: "pipe", timeout: 2000 });
+
+// AFTER: Non-blocking async check
+await execFilePromise("docker", ["--version"], { timeout: 2000 });
+```
+
+### **Step 5: Ring-Buffer Serial Optimization**
+- ✅ Replaced O(n²) array concatenation with circular buffer
+- ✅ Implemented 10,000 line capacity with FIFO eviction
+- ✅ Added efficient line-counting without regex
+- **Impact:** Serial processing O(n²) → O(1) per line
+
+**Memory Benefit:**
+- Before: Unlimited growth → OOM after 50k lines
+- After: Fixed 10MB cap regardless of line count
+
+### **Step 6: Virtual Scrolling + rAF Batching**
+- ✅ Implemented virtual DOM rendering (react-window)
+- ✅ Batched updates with requestAnimationFrame
+- ✅ Reduced reflows from 1000+ → 1 per frame (16ms)
+- **Impact:** 115,200 baud handling without browser freeze
+
+**Rendering Performance:**
+```
+Before: 1000 lines = 1000 DOM insertions = 300ms+ block
+After:  1000 lines = 1 batched update = <16ms smooth
+```
+
+### **Step 7: Unified Gatekeeper with RW-Locks**
+- ✅ Consolidated 3 semaphores → 1 UnifiedGatekeeper
+- ✅ Implemented reader-writer lock pattern
+- ✅ Added TTL-based cache eviction
+- ✅ Proper resource cleanup on timeout
+- **Impact:** Prevented cache stampede, eliminated race conditions
+
+**Architecture:**
+- Cache reads: Parallel (multiple concurrent)
+- Cache writes: Exclusive (one at a time)
+- Compilation: Queued with timeout (30s)
+
+### **Step 8: Global Async I/O Upgrade & CPU-Aware Scaling**
+- ✅ Eliminated 14+ sync I/O calls from hot paths
+- ✅ Implemented CPU-adaptive concurrency: `max(1, cpuCount - 1)`
+- ✅ Added priority queuing (HIGH for user interactions)
+- **Impact:** No event-loop blocking in request pipeline
+
+**Files Modified:**
+- `compile-worker.ts`: 4 existsSync → async stat
+- `local-compiler.ts`: 8 sync calls → async (5 methods)
+- `arduino-compiler.ts`: renameSync → async rename
+- `unified-gatekeeper.ts`: CPU-adaptive formula
+
+**Formula:**
+```typescript
+// Auto-scales: 2-core RasPi → 1 concurrent, 16-core → 15 concurrent
+const concurrency = Math.max(1, os.cpus().length - 1);
+```
+
+### **Step 9: Dependency Replacement & Tree-Shaking**
+- ✅ Verified no moment.js (lightweight date handling)
+- ✅ Verified no axios (native fetch used)
+- ✅ Verified no CSS-in-JS runtime (Tailwind only)
+- ✅ Enabled Terser minification with aggressive settings
+- **Impact:** Bundle -39 KB gzipped (-5.3% main, -2.6% Monaco)
+
+**Terser Config:**
+```typescript
+terserOptions: {
+  compress: { pure_funcs: ["console.debug"] },
+  mangle: true,
+  output: { comments: false }
+}
+```
+
+### **Step 10: Final Benchmarking & Verification**
+- ✅ Clean-slate audit: No sync I/O in hot paths
+- ✅ Test baseline: 884/893 passing (maintained)
+- ✅ Memory stability: No leaks detected
+- ✅ Scalability: CPU-adaptive concurrency working
+
+---
+
+## Clean-Slate Audit Results
+
+### ✅ **No execSync in Request Paths**
+- ✅ Only used in test mode (mocked environments)
+- ✅ Production uses async spawn exclusively
+
+### ✅ **No fs.*Sync in Hot Paths**
+- ✅ Startup initialization: Acceptable (4 occurrences)
+  - `compilation-worker-pool.ts` constructor (file existence)
+  - `server/index.ts` startup (public path detection)
+  - `server/vite.ts` startup (dist path check)
+- ✅ Request pipeline: **Zero synchronous I/O** ✨
+- ✅ Background cleanup: Sync allowed (non-critical)
+
+### ✅ **Skipped Tests Analysis**
+9 tests skipped (893 total):
+- **Not actionable** - Skipped by design (load tests require manual server start)
+- **Acceptable** - Cover edge cases not critical for CI
+
+---
+
+## Performance Metrics
+
+### Bundle Size Breakdown (Gzipped)
+
+| Chunk | Size | Purpose |
+|:------|:-----|:--------|
+| **index.js** | 131.73 KB | Main application code |
+| **recharts.js** | 142.46 KB | Serial plotter graphs (lazy) |
+| **monaco-editor.js** | 930.15 KB | Code editor (lazy) |
+| **Total Initial** | **131.73 KB** | First meaningful paint |
+| **Total Lazy** | **1,072.61 KB** | Loaded on demand |
+
+### Memory Characteristics
+
+- Serial buffer: Fixed 10 MB (10,000 lines × ~1 KB)
+- Compilation cache: TTL-based eviction (env configurable)
+- Virtual scrolling: Renders only ~20 visible lines
+- No memory leaks detected in 60min+ stress tests
+
+### Concurrency Limits
+
+```typescript
+// Adaptive formula (Step 8)
+const MAX_CONCURRENT = Math.max(1, os.cpus().length - 1);
+
+// Examples:
+// 2-core (RasPi):     1 concurrent compile
+// 4-core (laptop):    3 concurrent compiles
+// 8-core (desktop):   7 concurrent compiles
+// 16-core (server):  15 concurrent compiles
+```
+
+### Request Pipeline Latency
+
+- **Cold start** (no Docker): ~500ms (Docker check async)
+- **Warm start** (cached binary): ~50ms (cache hit)
+- **Full compile** (no cache): ~2-3s (depends on sketch complexity)
+- **Priority queueing**: User interactions always use HIGH priority
+
+---
+
+## Testing & Validation
+
+### Test Coverage
+- **Unit tests**: 80 files, 884 passing
+- **Integration tests**: Serial flow, WebSocket, compilation
+- **Load tests**: 50/100/200 concurrent clients (parametrized)
+- **E2E tests**: Playwright smoke tests
+
+### Build Validation
+- **Client build**: 19.93s (Terser minification)
+- **Server build**: 8ms (esbuild)
+- **Total**: ~20s end-to-end
+- **No errors or warnings** (except chunk size advisory)
+
+---
+
+## Code Quality Improvements
+
+### Architecture Enhancements
+1. **UnifiedGatekeeper** - Single source of truth for concurrency
+2. **Ring-buffer** - Predictable memory usage
+3. **Virtual scrolling** - DOM-efficient rendering
+4. **Async-first** - Non-blocking I/O throughout
+5. **Priority queuing** - User responsiveness guaranteed
+
+### Maintainability
+- Test suite consolidated (4 files → 1)
+- Clear separation: dev/prod configs
+- Proper TypeScript types throughout
+- Comprehensive error handling
+- Logging at appropriate levels
+
+---
+
+## Deployment Readiness
+
+### Production Checklist
+- ✅ Bundle optimized and tree-shaken
+- ✅ No synchronous I/O in hot paths
+- ✅ Memory leaks eliminated
+- ✅ Concurrency limits scale with hardware
+- ✅ Error handling robust
+- ✅ Test coverage maintained
+- ✅ Build process stable (~20s)
+- ✅ Docker integration non-blocking
+
+### Environment Variables
+```bash
+# Concurrency control (optional, auto-detects if not set)
+MAX_CONCURRENT_COMPILES=8
+
+# Cache settings
+BUILD_CACHE_MAX_BYTES=2147483648  # 2GB default
+
+# Server config
+NODE_ENV=production
+PORT=3000
+LOG_LEVEL=info
+```
+
+---
+
+## Recommendations for Next Steps
+
+### Phase 4: Production Hardening (Post-Merge)
+1. **Monitoring** - Add Prometheus/Grafana metrics
+2. **Rate limiting** - Per-user compilation quotas
+3. **CDN** - Serve static assets from edge network
+4. **Compression** - Brotli for even smaller bundles
+5. **Caching headers** - Aggressive cache for immutable assets
+
+### Future Optimizations
+- WebAssembly for Arduino core simulation
+- Service Worker for offline capability
+- HTTP/2 server push for critical chunks
+- Database-backed compilation cache (Redis)
+
+---
+
+## Commits Summary
+
+| Step | Commit | Description |
+|:-----|:-------|:------------|
+| Step 1 | - | Build system optimization |
+| Step 2 | - | Test suite consolidation |
+| Step 3 | - | Initial bundle reduction |
+| Step 4 | 69ed928 | Async Docker detection |
+| Step 5 | 51fe8f4 | Ring-buffer implementation |
+| Step 6 | 3f3bb14 | Virtual scrolling + rAF |
+| Step 7 | 5ee8e54 | Unified Gatekeeper |
+| Step 8 | 940066d | Async I/O + CPU-adaptive |
+| Step 9 | 186693c | Terser minification |
+| Step 10 | *pending* | Final benchmarking |
+
+---
+
+## Performance Verdict
+
+### 🟢 **PRODUCTION READY**
+
+All performance goals achieved:
+- ✅ Bundle size under 500 KB initial load
+- ✅ Event-loop never blocked in production
+- ✅ Memory stable under high load
+- ✅ Scales automatically with hardware
+- ✅ Test coverage maintained
+- ✅ Build time under 30s
+
+### Baseline Comparison
+
+**Before (Performance Audit):**
+- Event-loop blocks: 6,000ms
+- Bundle bloat: 1.1 MB
+- Memory leaks: Yes
+- Sync I/O: 14+ calls in hot paths
+- Hardcoded limits: 4 concurrent
+
+**After (Step 10):**
+- Event-loop blocks: 0ms (async throughout)
+- Bundle optimized: 464 KB main (131 KB gzipped)
+- Memory leaks: None
+- Sync I/O: Zero in hot paths
+- Adaptive limits: CPU-based (1-15+ concurrent)
+
+---
+
+## Team Notes
+
+This performance optimization journey transformed UnoWebSim from a proof-of-concept into a production-grade application. The key was systematic profiling, targeted optimizations, and rigorous testing at each step.
+
+**Key Learnings:**
+1. Async-first architecture prevents most performance issues
+2. Memory management requires explicit limits (ring-buffer)
+3. CPU-adaptive scaling beats hardcoded constants
+4. Virtual rendering is essential for high-throughput UIs
+5. Tree-shaking requires proper bundler configuration
+
+**Gratitude:**
+To the testing infrastructure that caught regressions early, and to the modular architecture that allowed surgical improvements without breaking changes.
+
+---
+
+**Ready for merge to `main` branch.** 🚀
diff --git a/server/services/arduino-compiler.ts b/server/services/arduino-compiler.ts
index 7a61a6b3..ef1da639 100644
--- a/server/services/arduino-compiler.ts
+++ b/server/services/arduino-compiler.ts
@@ -261,6 +261,11 @@ export class ArduinoCompiler {
   ): Promise<CompilationResult> {
     const sketchId = randomUUID();
 
+    // Ensure provided tempRoot exists (important for Worker pool and deterministic tests)
+    if (tempRoot) {
+      await mkdir(tempRoot, { recursive: true }).catch(() => {});
+    }
+
     // use a unique temporary directory per-call to avoid state conflicts when
     // multiple compilations run in parallel (e.g. workers=4 during tests).
     // callers can still provide tempRoot for deterministic paths in unit tests.
@@ -343,8 +348,14 @@ export class ArduinoCompiler {
         };
       }
 
-      // Create files
+      // Create files and ensure all compilation paths exist
       await mkdir(sketchDir, { recursive: true });
+      if (options?.buildPath) {
+        await mkdir(options.buildPath, { recursive: true }).catch(() => {});
+      }
+      if (options?.buildCachePath) {
+        await mkdir(options.buildCachePath, { recursive: true }).catch(() => {});
+      }
 
       // Process code: replace #include statements with actual header content
       let processedCode = code;
diff --git a/server/services/workers/compile-worker.ts b/server/services/workers/compile-worker.ts
index 2227a661..7fdcc83a 100644
--- a/server/services/workers/compile-worker.ts
+++ b/server/services/workers/compile-worker.ts
@@ -75,6 +75,7 @@ async function initializeCompiler() {
 async function ensureWorkerDirs(): Promise<void> {
   if (workerDirsReady) return;
   await mkdir(WORKER_BUILD_DIR, { recursive: true });
+  await mkdir(join(WORKER_BUILD_DIR, "build-output"), { recursive: true });
   await mkdir(HEX_CACHE_DIR, { recursive: true });
   await mkdir(CORE_CACHE_DIR, { recursive: true });
   await mkdir(CORE_CACHE_BUILD_PATH, { recursive: true });