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/console_windows.go

@@ -0,0 +1,54 @@
+//go:build windows
+
+package main
+
+// Windows-only: with -H=windowsgui the binary is registered as a GUI
+// subsystem app, so double-clicking from the Desktop shortcut does NOT
+// spawn a console window (good for the desktop UX). The downside is that
+// sub-commands like `muyue scan`, `muyue version`, `muyue install-shortcuts`
+// produce no output when invoked from cmd.exe.
+//
+// Workaround: at process start, try to attach to the parent's console via
+// kernel32!AttachConsole(ATTACH_PARENT_PROCESS). If the parent has a console
+// (i.e. we were launched from cmd.exe / PowerShell), stdout/stderr/stdin are
+// rebound to it. If not (Explorer double-click), the call fails silently and
+// the binary runs without any console — exactly what we want.
+
+import (
+	"log"
+	"os"
+	"syscall"
+)
+
+const attachParentProcess = ^uint32(0) // -1 cast to DWORD
+
+func init() {
+	kernel32, err := syscall.LoadLibrary("kernel32.dll")
+	if err != nil {
+		return
+	}
+	defer syscall.FreeLibrary(kernel32)
+	attachConsole, err := syscall.GetProcAddress(kernel32, "AttachConsole")
+	if err != nil {
+		return
+	}
+	r0, _, _ := syscall.SyscallN(attachConsole, uintptr(attachParentProcess))
+	if r0 == 0 {
+		return // parent has no console (Explorer launch) — stay silent
+	}
+	// Re-bind the standard streams to the freshly attached console so
+	// fmt.Println / log output appear in the parent terminal.
+	if h, err := syscall.GetStdHandle(syscall.STD_OUTPUT_HANDLE); err == nil && h != 0 {
+		os.Stdout = os.NewFile(uintptr(h), "stdout")
+	}
+	if h, err := syscall.GetStdHandle(syscall.STD_ERROR_HANDLE); err == nil && h != 0 {
+		os.Stderr = os.NewFile(uintptr(h), "stderr")
+	}
+	if h, err := syscall.GetStdHandle(syscall.STD_INPUT_HANDLE); err == nil && h != 0 {
+		os.Stdin = os.NewFile(uintptr(h), "stdin")
+	}
+	// log.Default() captured the original os.Stderr at init time — repoint it
+	// at the freshly attached console so log.Printf calls (e.g. desktop.Run)
+	// surface in the parent terminal.
+	log.SetOutput(os.Stderr)
+}