feat: comprehensive project improvements

- Fix 14 Clippy warnings across server and bot-sdk
- Add 67 unit tests (32 bot-sdk, 34 server, 1 doctest)
- Add Prometheus metrics endpoint (/api/metrics)
- Add structured JSON logging (EIFELDC_LOG_FORMAT=json)
- Add release workflow (Docker push + GitHub Release + Tauri builds)
- Add rate limiting middleware (EIFELDC_RATE_LIMIT)
- Add CORS restriction (EIFELDC_CORS_ORIGINS)
- Add session token expiry (EIFELDC_SESSION_TTL)
- Add input validation (username/password/homeserver length limits)
- Add upload size limit (EIFELDC_MAX_UPLOAD_MB)
- Upgrade Tauri client from v1 to v2
- Add session store with SQLite persistence
- Add proper error types and cleanup across all crates
- Format all code with cargo fmt
- Update CI pipeline with fmt, clippy, test, frontend, and Tauri checks
- Add README with full API reference and setup guide

client/src-ui/package.json

@@ -18,5 +18,8 @@
     "tslib": "^2",
     "typescript": "^5.9.3",
     "vite": "^5"
+  },
+  "dependencies": {
+    "livekit-client": "^2.18.7"
   }
 }