fix: create runtime directory on daemon startup

Author: alysnnix

internal/daemon/daemon.go

@@ -55,6 +55,11 @@ func (d *Daemon) Run() error {
 	sigCh := make(chan os.Signal, 1)
 	signal.Notify(sigCh, syscall.SIGTERM, syscall.SIGINT, syscall.SIGHUP)
 
+	// Ensure runtime directory exists
+	if err := os.MkdirAll(filepath.Dir(d.socketPath), 0755); err != nil {
+		return fmt.Errorf("failed to create runtime directory: %w", err)
+	}
+
 	// Write PID file
 	pidPath := filepath.Join(filepath.Dir(d.socketPath), "devproxy.pid")
 	os.WriteFile(pidPath, []byte(fmt.Sprintf("%d", os.Getpid())), 0644)