fix(windows): GUI subsystem + parent-console attach + canonical muyue.exe (v0.7.5)

Three Windows install/launch issues reported by the user:

1. Double-click on Desktop shortcut → dialog "This is a command line
   tool. You need to open cmd.exe and run it from there."
   Cause: charmbracelet/huh detects no TTY when launched via Explorer
   and aborts. Fix:
   - cmd/muyue/commands/root.go: skip RunFirstTimeSetup when
     os.Stdin is not a character device; persist config.Default()
     and let the React onboarding wizard handle first-run UX.
   - ci-{main,develop}.yml: build Windows binaries with
     -ldflags="-H=windowsgui" so the .exe is a GUI subsystem app —
     no console window flashes on double-click.

2. CLI sub-commands (`muyue scan`, `muyue install-shortcuts`, etc.)
   would lose all output under -H=windowsgui when launched from
   cmd.exe / PowerShell. Mitigation:
   - cmd/muyue/console_windows.go (new, build-tagged): on init(),
     call kernel32!AttachConsole(ATTACH_PARENT_PROCESS). If the
     parent has a console, rebind os.Stdout/os.Stderr/os.Stdin to
     it and call log.SetOutput(os.Stderr) so existing log.Printf
     calls surface. If no parent console (Explorer), exit silently.

3. After install, `muyue` not recognized in PowerShell.
   Causes: (a) the extracted binary is muyue-windows-amd64.exe, not
   muyue.exe; (b) the user PATH update by install-shortcuts doesn't
   propagate to the existing PowerShell session.
   Fix in install-shortcuts:
   - Copy self to <installDir>/muyue.exe (rename impossible — the
     running .exe is locked on Windows) so `muyue` resolves once
     PATH is set.
   - Update Desktop + Start Menu .lnk to target the canonical
     muyue.exe rather than the platform-suffixed binary.
   - Print the line `$env:Path += ';<installDir>'` for the user to
     paste, refreshing the current session immediately.
   - ci-main.yml install snippet bumps to 5 lines, last being
     `$env:Path += ";$dest"`.

- internal/version/version.go: 0.7.4 → 0.7.5
- CHANGELOG.md: v0.7.5 entry covers all three fixes

cmd/muyue/commands/root.go

@@ -24,30 +24,61 @@ func Execute() error {
 	return rootCmd.Execute()
 }
 
+// isInteractiveStdin reports whether os.Stdin is connected to a real terminal.
+// Used to decide between the TUI first-time setup (huh forms) and a no-op
+// fallback that defers onboarding to the web wizard. Returns false when the
+// binary is launched by a double-click on Windows (Explorer attaches a pseudo
+// console without a usable TTY) — which is the exact case where huh prints
+// "This is a command line tool. You need to open cmd.exe and run it from there."
+// and exits.
+func isInteractiveStdin() bool {
+	stat, err := os.Stdin.Stat()
+	if err != nil {
+		return false
+	}
+	return (stat.Mode() & os.ModeCharDevice) != 0
+}
+
 func loadOrSetupConfig() *config.MuyueConfig {
 	if !config.Exists() {
-		fmt.Println("First time setup detected!")
-		cfg, err := profiler.RunFirstTimeSetup()
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Setup error: %v\n", err)
-			os.Exit(1)
-		}
+		// No config yet. If we have a real terminal, run the rich TUI setup
+		// (huh forms). Otherwise — typically when the user double-clicked the
+		// shortcut on Windows — write defaults silently and let the React
+		// onboarding wizard handle the real first-run flow once the browser
+		// opens. This avoids huh aborting with "This is a command line tool".
+		if isInteractiveStdin() {
+			fmt.Println("First time setup detected!")
+			cfg, err := profiler.RunFirstTimeSetup()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Setup error: %v\n", err)
+				os.Exit(1)
+			}
 
-		for i := range cfg.AI.Providers {
-			if cfg.AI.Providers[i].Active && cfg.AI.Providers[i].APIKey == "" {
-				key, err := profiler.AskAPIKey(cfg.AI.Providers[i].Name)
-				if err == nil && key != "" {
-					cfg.AI.Providers[i].APIKey = key
+			for i := range cfg.AI.Providers {
+				if cfg.AI.Providers[i].Active && cfg.AI.Providers[i].APIKey == "" {
+					key, err := profiler.AskAPIKey(cfg.AI.Providers[i].Name)
+					if err == nil && key != "" {
+						cfg.AI.Providers[i].APIKey = key
+					}
 				}
 			}
+
+			if err := config.Save(cfg); err != nil {
+				fmt.Fprintf(os.Stderr, "Save error: %v\n", err)
+				os.Exit(1)
+			}
+
+			fmt.Println("\nSetup complete! Starting muyue...")
+			return cfg
 		}
 
+		// Non-interactive — skip the TUI, persist defaults, web onboarding
+		// will fill in the profile / API keys.
+		cfg := config.Default()
 		if err := config.Save(cfg); err != nil {
 			fmt.Fprintf(os.Stderr, "Save error: %v\n", err)
 			os.Exit(1)
 		}
-
-		fmt.Println("\nSetup complete! Starting muyue...")
 		return cfg
 	}