Label jenis aplikasi dengan auto-detect (Go/AppImage/Electron/Script/Windows/Binary/PWA)

- internal/shortcut/kind.go: deteksi dari isi berkas - build info Go, magic
  AppImage, resources/*.asar untuk Electron, shebang untuk script, MZ untuk .exe
- .exe Windows kini boleh dipasang dan dijalankan lewat wine (Exec=wine <path>);
  kalau wine tidak terpasang, install ditolak dengan pesan jelas
- metadata menyimpan kind; chip jenis ditampilkan di setiap baris shortcut
  (data lama tetap tampil sebagai Executable/PWA)
- dialog menampilkan hasil deteksi setelah berkas dipilih, mis. 'winbox.exe - windows'
- README: bagian label otomatis + screenshot baru

internal/shortcut/kind_test.go

@@ -0,0 +1,80 @@
+package shortcut
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDetectKind(t *testing.T) {
+	dir := t.TempDir()
+
+	write := func(name string, head []byte) string {
+		path := filepath.Join(dir, name)
+		if err := os.WriteFile(path, append(head, make([]byte, 64)...), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		return path
+	}
+
+	elf := []byte{0x7f, 'E', 'L', 'F', 0x02, 0x01, 0x01, 0x00}
+
+	cases := []struct {
+		name string
+		path string
+		want string
+	}{
+		{"windows exe", write("winbox.exe", []byte("MZ\x90\x00")), KindWindows},
+		{"script", write("tool.sh", []byte("#!/bin/sh\n")), KindScript},
+		{"appimage", write("app.AppImage", append(append([]byte{}, elf...), 'A', 'I', 0x02, 0x00)), KindAppImage},
+		{"binary biasa", write("binary", elf), KindBinary},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := DetectKind(c.path); got != c.want {
+				t.Errorf("DetectKind() = %q, mau %q", got, c.want)
+			}
+		})
+	}
+
+	// binary Go: test ini sendiri hasil build Go, jadi harus terdeteksi "go"
+	exe, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := DetectKind(exe); got != KindGo {
+		t.Errorf("DetectKind(test binary) = %q, mau %q", got, KindGo)
+	}
+}
+
+func TestDetectKindElectron(t *testing.T) {
+	dir := t.TempDir()
+	app := filepath.Join(dir, "myapp")
+	if err := os.WriteFile(app, append([]byte{0x7f, 'E', 'L', 'F', 0x02, 0x01, 0x01, 0x00}, make([]byte, 32)...), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(filepath.Join(dir, "resources"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "resources", "app.asar"), []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	if got := DetectKind(app); got != KindElectron {
+		t.Errorf("DetectKind(electron) = %q", got)
+	}
+}
+
+func TestDetectKindUnknownFile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "catatan.txt")
+	if err := os.WriteFile(path, []byte("halo"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if got := DetectKind(path); got != "" {
+		t.Errorf("teks biasa tidak punya kind, dapat %q", got)
+	}
+	if got := DetectKind(filepath.Join(t.TempDir(), "tidak-ada")); got != "" {
+		t.Errorf("berkas tidak ada harus kosong, dapat %q", got)
+	}
+}