feat: enhance Synology Photos integration with OTP, SSL skip, and better UX

- Fix endpoint path: users now provide full base URL (e.g. https://nas:5001/photo)
- Add OTP/2FA field for Synology login
- Add skip SSL verification option (DB column + checkbox UI)
- Add device ID (synology_did) column for session tracking
- Trigger in-app notification when Synology session is cleared
- Show disconnection banner in MemoriesPanel
- Add URL hint in provider settings
- Map Synology API error codes to human-readable messages
- Update i18n for all locales

server/tests/integration/memories-synology.test.ts

@@ -39,7 +39,7 @@ vi.mock('../../src/config', () => ({
   ENCRYPTION_KEY: 'a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2a3b4c5d6a7b8c9d0e1f2',
   updateJwtSecret: () => {},
 }));
-vi.mock('../../src/websocket', () => ({ broadcast: vi.fn() }));
+vi.mock('../../src/websocket', () => ({ broadcast: vi.fn(), broadcastToUser: vi.fn() }));
 
 // ── SSRF guard mock — routes all Synology API calls to fake responses ─────────
 vi.mock('../../src/utils/ssrfGuard', async () => {