Add standalone FastAPI server backend (Phase 3)

Build a complete standalone web server for Immich album change
notifications, independent of Home Assistant. Uses the shared
core library from Phase 1.

Server features:
- FastAPI with async SQLite (SQLModel + aiosqlite)
- Multi-user auth with JWT (admin/user roles, setup wizard)
- CRUD APIs: Immich servers, album trackers, message templates,
  notification targets (Telegram + webhook), user management
- APScheduler background polling per tracker
- Jinja2 template rendering with live preview
- Album browser proxied from Immich API
- Event logging and dashboard status endpoint
- Docker deployment (single container, SQLite in volume)

39 API routes, 14 integration tests passing.

Also adds Phase 6 (Claude AI Telegram bot enhancement) to the
primary plan as an optional future phase.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plans/primary-plan.md

@@ -186,7 +186,7 @@ async def _execute_telegram_notification(self, ...):
 - Verify identical behavior with real Immich server
 - **Subplan**: `plans/phase-2-haos-refactor.md`
 
-### Phase 3: Build Server Backend `[ ]`
+### Phase 3: Build Server Backend `[x]`
 - FastAPI app with database, scheduler, API endpoints
 - Telegram + webhook notification providers
 - Jinja2 template engine with variable system matching blueprint
@@ -203,6 +203,14 @@ async def _execute_telegram_notification(self, ...):
 - Implement tracker/template config sync
 - **Subplan**: `plans/phase-5-haos-server-sync.md`
 
+### Phase 6: Claude AI Telegram Bot Enhancement (Optional) `[ ]`
+- Integrate Claude AI to enhance the Telegram notification bot
+- Enable conversational interactions: users can ask questions about their albums, get summaries, request specific photos
+- AI-powered message formatting: intelligent caption generation, album descriptions
+- Smart notification filtering: AI decides notification importance/relevance
+- Natural language tracker configuration via Telegram chat
+- **Subplan**: `plans/phase-6-claude-ai-bot.md`
+
 ---
 
 ## Verification