feat: integrate rclone WebDAV backup for PC-to-PC file sync

Source PC serves backups/ folder via rclone WebDAV server (auto-starts with app).
Receiver PC pulls backups on schedule using rclone sync.
Network Backup UI now has two tabs: Rclone and API Key.
Rclone installed automatically via postinstall script.

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

apps/Backend/src/app.ts

@@ -10,6 +10,7 @@ import { authenticateJWT } from "./middlewares/auth.middleware";
 import networkBackupPublicRoutes from "./routes/network-backup-public";
 import dotenv from "dotenv";
 import { startBackupCron } from "./cron/backupCheck";
+import { autoStartServer } from "./services/rcloneService";
 import path from "path";
 
 dotenv.config();
@@ -87,5 +88,6 @@ app.use(errorHandler);
 
 //startig cron job
 startBackupCron();
+autoStartServer();
 
 export default app;