feat(release): attach native Arch package and repackage for AUR

Update release workflow to detect and attach the native Arch package.
Switch the binary AUR recipe to repackage the .pkg.tar.zst. Adjust
checksums and packaging steps so the output carries only the native
payload without bundling upstream package metadata.

- Attach the native .pkg.tar.zst to Gitea releases.
- Rework binary AUR recipe to extract usr from the native package.
- Update README to document using the native Arch package.

PKGBUILD-bin

@@ -3,43 +3,23 @@
 pkgname=gitty-desktop-bin
 pkgver=2026.8.4
 pkgrel=1
-pkgdesc="A lightweight, modern Git client built with Tauri (prebuilt AppImage)"
+pkgdesc="A lightweight, modern Git client built with Tauri (prebuilt Arch package)"
 arch=('x86_64')
 url="https://git.cbsk-tech.de/Christoph/GitLite"
 license=('MIT')
-depends=('fuse2' 'git' 'webkit2gtk-4.1' 'gtk3' 'hicolor-icon-theme' 'libappindicator-gtk3' 'librsvg' 'xdotool')
+depends=('git' 'webkit2gtk-4.1' 'gtk3' 'hicolor-icon-theme' 'libappindicator-gtk3' 'librsvg' 'xdotool')
 provides=('gitty-desktop')
 conflicts=('gitty-desktop')
 options=('!strip')
 
-_appimage="Gitty_${pkgver}_amd64.AppImage"
-_artifact_url="https://cdn.cbsk-tech.de/gitty/${pkgver}/${_appimage}"
-_tag=2026.8.4
-source=("${_appimage}::${_artifact_url}"
-        "gitty-desktop.png::${url}/raw/tag/${_tag}/src-tauri/icons/icon.png")
-sha256sums=('SKIP'
-            'SKIP')
+_package="gitty-desktop-${pkgver}-1-x86_64.pkg.tar.zst"
+_artifact_url="https://git.cbsk-tech.de/Christoph/GitLite/releases/download/${pkgver}/${_package}"
+source=("${_package}::${_artifact_url}")
+noextract=("${_package}")
+sha256sums=('SKIP')
 
 package() {
-  install -Dm755 "$srcdir/$_appimage" \
-    "$pkgdir/opt/$pkgname/gitty-desktop.AppImage"
-  install -d "$pkgdir/usr/bin"
-  ln -s "/opt/$pkgname/gitty-desktop.AppImage" \
-    "$pkgdir/usr/bin/gitty-desktop"
-
-  install -Dm644 "$srcdir/gitty-desktop.png" \
-    "$pkgdir/usr/share/icons/hicolor/512x512/apps/gitty-desktop.png"
-
-  install -d "$pkgdir/usr/share/applications"
-  cat > "$pkgdir/usr/share/applications/gitty-desktop.desktop" <<-EOF
-	[Desktop Entry]
-	Type=Application
-	Name=Gitty
-	Comment=$pkgdesc
-	Exec=gitty-desktop
-	Icon=gitty-desktop
-	Terminal=false
-	Categories=Development;RevisionControl;
-	StartupWMClass=gitty
-	EOF
+  # Extract only the native package payload, without carrying its package
+  # metadata (.PKGINFO, .BUILDINFO and .MTREE) across.
+  bsdtar -xf "$srcdir/$_package" -C "$pkgdir" usr
 }