Add desktop integration and Arch PKGBUILD

- steam-dice.svg: flat dice icon on Steam-blue gradient
- steam-dice.desktop: launcher entry under Game category
- PKGBUILD: steam-dice-git, builds from GitHub source
- Use setDesktopFileName for correct Wayland WM_CLASS, with
  local SVG fallback when running from the source tree

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

PKGBUILD

@@ -0,0 +1,29 @@
+# Maintainer: Mollusk <silvernode@gmail.com>
+pkgname=steam-dice-git
+_pkgname=steam-dice
+pkgver=r0.0000000
+pkgrel=1
+pkgdesc="A PyQt6 desktop app that picks a random game from your Steam library"
+arch=('any')
+url="https://github.com/silvernode/steam-dice"
+license=('GPL-2.0-only')
+depends=('python' 'python-pyqt6' 'python-requests' 'python-keyring' 'xdg-utils')
+makedepends=('git')
+provides=("$_pkgname")
+conflicts=("$_pkgname")
+source=("$_pkgname::git+https://github.com/silvernode/steam-dice.git")
+sha256sums=('SKIP')
+
+pkgver() {
+    cd "$_pkgname"
+    printf "r%s.%s" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"
+}
+
+package() {
+    cd "$_pkgname"
+    install -Dm755 steam_dice.py "$pkgdir/usr/bin/steam-dice"
+    install -Dm644 steam-dice.desktop "$pkgdir/usr/share/applications/steam-dice.desktop"
+    install -Dm644 steam-dice.svg "$pkgdir/usr/share/icons/hicolor/scalable/apps/steam-dice.svg"
+    install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$_pkgname/LICENSE"
+    install -Dm644 README.md "$pkgdir/usr/share/doc/$_pkgname/README.md"
+}