feat: add CalDAV synchronization with automatic sync

- Add CaldavService with tsdav/ical.js for CalDAV server communication
- Add CaldavController, CaldavRepository, and caldav routes
- Add client-side CaldavConfigService with sync(), config CRUD
- Add CalDAV settings UI with config load/save in settings screen
- Sync on login, auto-login (AuthGuard), periodic timer (calendar), and sync button
- Push single events to CalDAV on server-side create/update/delete
- Push all events to CalDAV after chat event confirmation
- Refactor ChatService to use EventService instead of direct EventRepository
- Rename CalDav/calDav to Caldav/caldav for consistent naming
- Add Radicale Docker setup for local CalDAV testing
- Update PlantUML diagrams and CLAUDE.md with CalDAV architecture

apps/server/src/services/CaldavService.test.ts

@@ -0,0 +1,11 @@
+// import { createLogger } from "../logging";
+// import { CaldavService } from "./CaldavService";
+//
+// const logger = createLogger("CaldavService-Test");
+//
+// const cdService = new CaldavService();
+//
+// test("print events", async () => {
+//   const client = await cdService.login();
+//   await cdService.pullEvents(client);
+// });