feat(myTischtennis): integrate Playwright for CAPTCHA handling and enhance login form functionality

- Added Playwright as a dependency to handle CAPTCHA challenges during login attempts.
- Implemented a new endpoint to retrieve the login form from myTischtennis, parsing necessary fields for user input.
- Enhanced the login process to utilize Playwright for browser automation when CAPTCHA is required.
- Updated the MyTischtennisDialog component to support local login form submission instead of using an iframe.
- Refactored the MyTischtennisController to include proxy functionality for serving resources and handling login submissions.
- Improved error handling and user feedback during login attempts, ensuring a smoother user experience.

backend/routes/myTischtennisRoutes.js

@@ -10,6 +10,9 @@ const router = express.Router();
 // GET /api/mytischtennis/login-page - Proxy für Login-Seite (für iframe)
 router.get('/login-page', myTischtennisController.getLoginPage);
 
+// GET /api/mytischtennis/proxy/* - Same-Origin-Proxy für mytischtennis Assets/APIs
+router.get('/proxy/*', myTischtennisController.proxyRemote);
+
 // POST /api/mytischtennis/login-submit - Proxy für Login-Form-Submission
 router.post('/login-submit', myTischtennisController.submitLogin);
 
@@ -25,6 +28,9 @@ router.get('/account', myTischtennisController.getAccount);
 // GET /api/mytischtennis/status - Check status (alle dürfen lesen)
 router.get('/status', myTischtennisController.getStatus);
 
+// GET /api/mytischtennis/login-form - Parse mytischtennis Login-Form
+router.get('/login-form', myTischtennisController.getLoginForm);
+
 // POST /api/mytischtennis/account - Create or update account (alle dürfen bearbeiten)
 router.post('/account', myTischtennisController.upsertAccount);