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/src/db/schema.ts

@@ -245,6 +245,7 @@ function createTables(db: Database.Database): void {
       label TEXT NOT NULL,
       input_type TEXT NOT NULL DEFAULT 'text',
       placeholder TEXT,
+      hint TEXT,
       required INTEGER DEFAULT 0,
       secret INTEGER DEFAULT 0,
       settings_key TEXT,