Fix codespace state refresh and improve setup flow (#214)

## Summary

Fixes two critical UX issues in the Catnip iOS app:

**Issue 1: Stale codespace state after deletion**
- After deleting a codespace in GitHub, the app shows stale "Access My
Codespace" button
- This leads to confusing Setup view with manual devcontainer
instructions when clicked
- **Fix:** Implemented verification caching with rate limiting to
refresh state on reconnect

**Issue 2: Confusing Setup flow**
- Generic Setup view doesn't guide users based on their GitHub state
- **Fix:** Smart routing based on user's repository state:
  - Zero repos → friendly "Create Repository" onboarding screen
  - Repos without Catnip → "Install Catnip" flow
  - Repos with Catnip → "Launch Codespace" flow

## Architecture

**Worker Side:**
- 60-second verification cache for `/v1/user/status` to reduce GitHub
API calls
- 10-second rate limiting on `?refresh=true` requests (dual-layer:
client + server)
- SSE setup events enriched with `next_action` field based on GitHub
repository state

**iOS Side:**
- Call `fetchUserStatus(forceRefresh: true)` on reconnect to get fresh
state
- Route users based on worker's `next_action` determination
- New friendly "Create Repository" guidance screen for zero-repo users

## Test Plan

- [x] Build succeeds (verified with xcodebuild)
- [ ] Manual testing: Delete codespace in GitHub, verify reconnect shows
correct flow
- [ ] Manual testing: Test zero-repo user sees "Create Repository"
screen
- [ ] Manual testing: Verify rate limiting prevents rapid refresh calls
- [ ] Deploy to production and monitor

## Implementation Details

### Worker Changes (Tasks 1-4)
- Added `VerificationCache` interface and helpers for Durable Object
storage
- Implemented cache storage routes (GET/PATCH
`/verification-cache/{username}`)
- Enhanced `/v1/user/status` with caching and rate limiting
- Added GitHub repository state checking to SSE setup events

### iOS Changes (Tasks 5-9)
- Updated `SSEEvent.setup` to include `nextAction` parameter
- Added client-side rate limiting to `CatnipInstaller.fetchUserStatus`
- Created `createRepository` phase and view for zero-repo users
- Updated `handleSSEEvent` to route based on `next_action`
- Updated `WorkspacesView` reconnect flow to refresh state before
navigation

## References

- Design doc: `docs/plans/2025-11-07-codespace-state-refresh-design.md`
- Implementation plan:
`docs/plans/2025-11-07-codespace-state-refresh.md`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude <claude@anthropic.com>
Co-authored-by: Claude <noreply@anthropic.com>

Author: 3 people

.gitignore

@@ -42,13 +42,17 @@ worker/**/*.js.map
 # crush
 .crush/
 
+# worktrees
+.worktrees/
+
 # secrets
 *.pem
 
 # reference files
 reference
 container/Dockerfile.backup
 public/*.jsonl
+docs/plans/
 
 # fallback frontend assets for local go builds (real assets are built in docker)
 # keep the dummy index.html but ignore anything else that gets copied here

README.md

@@ -38,6 +38,10 @@ Catnip is a web service that automates git worktree creation and runs in a conta
 
 ## ⚡ Quick Start
 
+### Mobile App
+
+Our iOS native interface is currently in beta. You can join the [TestFlight group](https://testflight.apple.com/join/dm8GahU7) to try the app today. The app will help you configure an existing GitHub repository with catnip as described below. Once setup you can fire up claude code on the go! Please share any bug reports or feedback.
+
 ### Github Codespaces / Devcontainers
 
 You can add Catnip to a `.devcontainer/devcontainer.json` in an existing GitHub repository. This gives you complete control over the environment that claude operates in. If you don't have a devcontainer config, add the following to your repo's github url: `/new/main?dev_container_template=1&filename=.devcontainer%2Fdevcontainer.json` to create one. Just add the catnip feature and ensure the port is forwarded: