fix: scope FileBrowser DB reset to restore-only path

Normal storage add/remove no longer nukes the FileBrowser database volume.
A .fb-reset flag file is written during restore and consumed on next startup.

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

controller/internal/web/server.go

@@ -114,8 +114,16 @@ func NewServer(cfg *config.Config, stackMgr *stacks.Manager, cpuCollector *syste
 		logger.Printf("[INFO] Auth: no password configured — dashboard is open")
 	}
 
-	// Sync FileBrowser config on startup to ensure mounts and sources are current
-	go s.SyncFileBrowserMounts()
+	// Sync FileBrowser config on startup to ensure mounts and sources are current.
+	// After a restore, a flag file signals that the database should be reset
+	// (stale source prefs from initial install). Consume the flag and reset.
+	fbResetFlag := filepath.Join(cfg.Paths.DataDir, ".fb-reset")
+	if _, err := os.Stat(fbResetFlag); err == nil {
+		os.Remove(fbResetFlag)
+		go s.SyncFileBrowserMountsReset()
+	} else {
+		go s.SyncFileBrowserMounts()
+	}
 
 	return s
 }