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-server/PKGBUILD

@@ -0,0 +1,63 @@
+# Maintainer: funman300 <funman300@gmail.com>
+
+pkgname=solitaire-quest-server
+pkgver=0.1.0
+pkgrel=1
+pkgdesc='Self-hosted sync server for Solitaire Quest (stats, achievements, leaderboards)'
+url='https://github.com/funman300/solitaire-quest'
+license=('MIT')
+arch=('x86_64')
+makedepends=('cargo' 'rust')
+depends=(
+    'gcc-libs'
+    'glibc'
+)
+backup=('etc/solitaire-quest-server/server.env')
+source=(
+    "$pkgname-$pkgver.tar.gz::https://github.com/funman300/solitaire-quest/archive/v$pkgver.tar.gz"
+    'solitaire-quest-server.service'
+    'server.env'
+)
+b2sums=('SKIP'
+        'SKIP'
+        'SKIP')
+
+prepare() {
+    cd "solitaire-quest-$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_server
+}
+
+check() {
+    cd "solitaire-quest-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    cargo test --frozen -p solitaire_server -p solitaire_sync
+}
+
+package() {
+    cd "solitaire-quest-$pkgver"
+    # Binary
+    install -Dm0755 -t "$pkgdir/usr/bin/" "target/release/solitaire_server"
+
+    # systemd service
+    install -Dm0644 "$srcdir/solitaire-quest-server.service" \
+        "$pkgdir/usr/lib/systemd/system/solitaire-quest-server.service"
+
+    # Environment file (contains JWT_SECRET, DATABASE_URL, SERVER_PORT)
+    install -Dm0640 "$srcdir/server.env" \
+        "$pkgdir/etc/solitaire-quest-server/server.env"
+
+    # License
+    install -Dm0644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+
+    # Self-hosting guide
+    install -Dm0644 README_SERVER.md \
+        "$pkgdir/usr/share/doc/$pkgname/README_SERVER.md"
+}

pkg/solitaire-quest-server/server.env

@@ -0,0 +1,15 @@
+# Solitaire Quest Server — environment configuration
+# This file is installed to /etc/solitaire-quest-server/server.env (mode 0640).
+# Edit these values before starting the service.
+
+# Path to the SQLite database file.
+# The directory must be writable by the solitaire-quest service user.
+DATABASE_URL=sqlite:///var/lib/solitaire-quest-server/solitaire.db
+
+# HS256 signing secret for JWT tokens.
+# Generate a strong secret with: openssl rand -hex 32
+# REQUIRED — server will refuse to start if unset.
+JWT_SECRET=changeme_generate_with_openssl_rand_hex_32
+
+# TCP port the server listens on.
+SERVER_PORT=8080

pkg/solitaire-quest-server/solitaire-quest-server.service

@@ -0,0 +1,23 @@
+[Unit]
+Description=Solitaire Quest Sync Server
+Documentation=https://github.com/funman300/solitaire-quest/blob/main/README_SERVER.md
+After=network.target
+
+[Service]
+Type=simple
+User=solitaire-quest
+Group=solitaire-quest
+EnvironmentFile=/etc/solitaire-quest-server/server.env
+ExecStart=/usr/bin/solitaire_server
+Restart=on-failure
+RestartSec=5s
+
+# Harden the service
+NoNewPrivileges=true
+PrivateTmp=true
+ProtectSystem=strict
+ProtectHome=true
+ReadWritePaths=/var/lib/solitaire-quest-server
+
+[Install]
+WantedBy=multi-user.target