✨ feat(bestdebrid): add BestDebrid web-login provider

- New BestDebrid web-login option (BrowserWindow + session.fetch)
- Uses bestdebrid.com/api/v1/generateLink with browser session cookies
- Login via BestDebrid website in embedded browser window
- Toggle "BestDebrid per Web-Login statt API-Token verwenden"
- Provider label shows "BestDebrid (Web)" or "BestDebrid (API)"
- Session persistence respects "Token merken" setting

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/main.ts

@@ -454,6 +454,10 @@ function registerIpcHandlers(): void {
     await controller.openAllDebridLoginWindow();
   });
 
+  ipcMain.handle(IPC_CHANNELS.OPEN_BESTDEBRID_LOGIN, async () => {
+    await controller.openBestDebridLoginWindow();
+  });
+
   ipcMain.handle(IPC_CHANNELS.GET_ALLDEBRID_HOST_INFO, async () => {
     return controller.getAllDebridHostInfo();
   });