feat: add Drone CI pipelines, Jest unit tests, and Prettier check

Add Drone CI with server build/test and format check pipelines.
Add unit tests for password utils and recurrenceExpander.
Add check_format script, fix Jest config to ignore dist/,
remove dead CaldavService.test.ts, apply Prettier formatting.

apps/server/src/services/AuthService.ts

@@ -44,5 +44,4 @@ export class AuthService {
 
     return { user, accessToken: "" };
   }
-
 }

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

@@ -1,11 +0,0 @@
-// 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);
-// });