chore(pkg): add Arch Linux PKGBUILDs for game client and sync server

- pkg/solitaire-quest/PKGBUILD: builds solitaire_app binary, depends on
  alsa-lib, libxkbcommon, systemd-libs (Bevy Linux requirements); check()
  runs only non-Bevy crates (solitaire_core, solitaire_sync) since Bevy
  integration tests require a GPU/display unavailable in chroot
- pkg/solitaire-quest-server/PKGBUILD: builds solitaire_server binary,
  installs systemd service unit and hardened environment file template
- pkg/solitaire-quest-server/solitaire-quest-server.service: systemd unit
  with ProtectSystem=strict, NoNewPrivileges, dedicated service user
- pkg/solitaire-quest-server/server.env: documented env template installed
  to /etc/solitaire-quest-server/server.env (mode 0640, listed in backup=)
- LICENSE: add MIT license
- Cargo.toml: add license = "MIT" to [workspace.package]
- All member crates: add license.workspace = true

Both PKGBUILDs follow the Arch Rust package guidelines:
  prepare() uses --locked + cargo fetch
  build() uses --frozen --release -p <crate>
  RUSTUP_TOOLCHAIN=stable and CARGO_TARGET_DIR=target set in each stage

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

pkg/solitaire-quest/PKGBUILD

@@ -0,0 +1,46 @@
+# Maintainer: funman300 <funman300@gmail.com>
+
+pkgname=solitaire-quest
+pkgver=0.1.0
+pkgrel=1
+pkgdesc='Cross-platform Klondike Solitaire with progression, achievements, and optional sync'
+url='https://github.com/funman300/solitaire-quest'
+license=('MIT')
+arch=('x86_64')
+makedepends=('cargo' 'rust')
+depends=(
+    'gcc-libs'
+    'glibc'
+    'alsa-lib'
+    'libxkbcommon'
+    'systemd-libs'   # libudev.so — required by Bevy input
+)
+source=("$pkgname-$pkgver.tar.gz::https://github.com/funman300/solitaire-quest/archive/v$pkgver.tar.gz")
+b2sums=('SKIP')
+
+prepare() {
+    cd "solitaire-quest-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    cargo fetch --locked --target "$(rustc -Vv | grep host | cut -d' ' -f2)"
+}
+
+build() {
+    cd "solitaire-quest-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    export CARGO_TARGET_DIR=target
+    cargo build --frozen --release -p solitaire_app
+}
+
+check() {
+    cd "solitaire-quest-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    # Only test the non-Bevy crates — Bevy integration tests require a GPU/display
+    # which is not available in a clean build environment.
+    cargo test --frozen -p solitaire_core -p solitaire_sync
+}
+
+package() {
+    cd "solitaire-quest-$pkgver"
+    install -Dm0755 -t "$pkgdir/usr/bin/" "target/release/solitaire_app"
+    install -Dm0644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+}