docs: document daemon mode for automatic file re-indexing

Add daemon mode documentation to README.md and CHANGELOG.md:
- Feature bullet point in "What you get" section
- Complete usage section with CLI commands and examples
- CHANGELOG entry with all daemon mode capabilities

Author: jruokola

CHANGELOG.md

@@ -7,6 +7,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+#### **Daemon Mode for Automatic Re-Indexing**
+- **Background file watching**: `codegraph daemon start <path>` launches a background process that monitors file changes
+- **Automatic re-indexing**: Changed files are automatically re-indexed using upsert semantics (no duplicates)
+- **Circuit breaker pattern**: SurrealDB health monitoring with exponential backoff for resilience
+- **PID file management**: Proper daemon lifecycle with process tracking and graceful shutdown
+- **CLI commands**:
+  - `codegraph daemon start <path>` - Start watching a project (with `--foreground` option for debugging)
+  - `codegraph daemon stop <path>` - Stop the daemon for a project
+  - `codegraph daemon status <path>` - Check daemon status (with `--json` option)
+- **Language and pattern filtering**: Supports `--languages`, `--exclude`, and `--include` flags
+- **Event coalescing**: Batches rapid file changes to avoid redundant re-indexing
+- **Feature flag**: `daemon` feature enables this functionality
+
 ### Removed
 - Dropped the transactional/versioning/branch N-API bindings plus their documentation; the native TypeScript surface now focuses on semantic search, graph analysis, and cloud configuration so it matches the Surreal-only architecture.
 - Replaced the native addon example with a semantic-search walkthrough and removed CLI-centric integration snippets that referenced the deleted CodeGraph CLI.

README.md

@@ -17,6 +17,7 @@ CodeGraph indexes your source code to a graph database, creates semantic embeddi
 - 📦 **NEW:** Node.js NAPI bindings for zero-overhead TypeScript integration
 - 🤖 **NEW:** Agentic code-agent tools with tier-aware multi-step reasoning
 - 🔄 **NEW:** Incremental indexing with SHA-256 file change detection—only re-index modified files
+- 👁️ **NEW:** Daemon mode for automatic file watching and re-indexing on changes
 - 🔬 **EXPERIMENTAL:** AutoAgents framework integration for improved agent orchestration
 
 ### Local Embeddings & Reranking (SurrealDB)
@@ -547,6 +548,42 @@ codegraph start stdio
 codegraph tools list
 ```
 
+### Daemon Mode (Automatic Re-Indexing)
+
+Keep your index up-to-date automatically by running the daemon:
+
+```bash
+# Start watching a project (runs in background)
+codegraph daemon start /path/to/project
+
+# Start in foreground for debugging
+codegraph daemon start /path/to/project --foreground
+
+# Filter by languages
+codegraph daemon start /path/to/project --languages rust,typescript
+
+# Exclude patterns
+codegraph daemon start /path/to/project --exclude "**/node_modules/**" --exclude "**/target/**"
+
+# Check daemon status
+codegraph daemon status /path/to/project
+codegraph daemon status /path/to/project --json  # JSON output
+
+# Stop the daemon
+codegraph daemon stop /path/to/project
+```
+
+**Features:**
+- 🔄 Automatic re-indexing when files change (create, modify, delete, rename)
+- ⚡ Event coalescing to batch rapid changes
+- 🛡️ Circuit breaker pattern for SurrealDB resilience
+- 📊 Session metrics tracking (batches processed, errors, etc.)
+
+**Note:** Requires the `daemon` feature flag:
+```bash
+cargo build --release -p codegraph-mcp --features "daemon,ai-enhanced,ollama"
+```
+
 **Note:** HTTP transport is not yet implemented with the official rmcp SDK. Use STDIO transport for all MCP integrations.
 
 ### Using with Claude Desktop