v12.3.3

## Issue Blowout 2026 — 25 bugs across worker, hooks, security, and search

### Security Hardening
- Bearer token authentication for all worker API endpoints with auto-generated tokens
- Path traversal protection on context write paths
- Per-user worker port derivation (37700 + uid%100) to prevent cross-user data leakage
- Rate limiting (300 req/min/IP) and reduced JSON body limit (50MB → 5MB)
- Caller headers can no longer override the bearer auth token

### Worker Stability
- Time-windowed RestartGuard replaces flat counter — prevents stranding pending messages on long sessions
- Idle session eviction prevents pool slot deadlock when all slots are full
- MCP loopback self-check uses process.execPath instead of bare 'node'
- Age-scoped failed message purge (1h retention) instead of clearing all
- RestartGuard decay anchored to real successes, not object creation time

### Search & Chroma
- FTS5 keyword fallback when ChromaDB is unavailable for all search handlers
- doc_type:'observation' filter on Chroma queries feeding observation hydration
- Project filtering passed to Chroma queries and SQLite hydration in all endpoints
- Bounded post-import Chroma sync with concurrency limit of 8
- FTS5 MATCH input escaped as quoted literal phrases to prevent syntax errors
- LIKE metacharacters escaped in prompt text search
- date_desc ordering respected in FTS session search

### Hooks Reliability
- Summarize hook wrapped in try/catch to prevent exit code 2 on network failures
- Session-init gated on health check success — no longer runs when worker unreachable
- Health-check wait loop added to UserPromptSubmit for Linux/WSL startup race

### Database & Performance
- Periodic WAL checkpoint and journal_size_limit to prevent unbounded WAL growth
- FTS5 availability cached at construction time (no DDL probe per query)
- _fts5Available downgraded when FTS table creation fails

### Viewer UI
- response.ok check added to settings save and initial load flows
- Auth failure handling in saveSettings