Add automated release workflow for tagged versions

Builds core binaries for all platforms (linux-x86_64, linux-aarch64,
macos-arm64, windows-x86_64) and creates a GitHub release with
auto-generated notes when a v* tag is pushed.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: JoeMatt

.github/workflows/release.yml

@@ -0,0 +1,100 @@
+name: Release
+
+on:
+  push:
+    tags: [ 'v*' ]
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - platform: linux-x86_64
+            artifact: virtualjaguar_libretro.so
+            os: ubuntu-latest
+            cc: gcc
+            cxx: g++
+
+          - platform: linux-aarch64
+            artifact: virtualjaguar_libretro.so
+            os: ubuntu-24.04-arm
+            cc: gcc
+            cxx: g++
+
+          - platform: macos-arm64
+            artifact: virtualjaguar_libretro.dylib
+            os: macos-latest
+            cc: clang
+            cxx: clang++
+
+          - platform: windows-x86_64
+            artifact: virtualjaguar_libretro.dll
+            os: windows-latest
+            cc: gcc
+            cxx: g++
+            shell: 'msys2 {0}'
+
+    name: build-${{ matrix.config.platform }}
+    runs-on: ${{ matrix.config.os }}
+
+    defaults:
+      run:
+        shell: ${{ matrix.config.shell || 'bash' }}
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up MSYS2
+      if: runner.os == 'Windows'
+      uses: msys2/setup-msys2@v2
+      with:
+        msystem: MINGW64
+        update: false
+        install: >-
+          mingw-w64-x86_64-gcc
+          make
+
+    - name: Build
+      run: make -j4 CC=${{ matrix.config.cc }} CXX=${{ matrix.config.cxx }}
+
+    - name: Package
+      run: |
+        mkdir -p dist
+        cp ${{ matrix.config.artifact }} dist/virtualjaguar_libretro-${{ matrix.config.platform }}${SUFFIX}
+      env:
+        SUFFIX: ${{ matrix.config.platform == 'windows-x86_64' && '.dll' || (matrix.config.platform == 'macos-arm64' && '.dylib' || '.so') }}
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: virtualjaguar_libretro-${{ matrix.config.platform }}
+        path: dist/
+        if-no-files-found: error
+
+  release:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Download all artifacts
+      uses: actions/download-artifact@v4
+      with:
+        path: artifacts/
+
+    - name: Create release
+      env:
+        GH_TOKEN: ${{ github.token }}
+      run: |
+        TAG="${GITHUB_REF_NAME}"
+        # Collect all built binaries
+        find artifacts/ -type f | sort
+
+        gh release create "${TAG}" \
+          --title "${TAG}" \
+          --generate-notes \
+          artifacts/virtualjaguar_libretro-*/*