ci: Add GitHub Actions workflows

- CI workflow for build, test, fmt, clippy
- Multi-platform builds (Linux, macOS x86_64, macOS ARM)
- Release workflow with artifact uploads
- Security audit integration

Note: Push with token that has 'workflow' scope

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/release.yml

@@ -0,0 +1,74 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  create-release:
+    name: Create Release
+    runs-on: ubuntu-latest
+    outputs:
+      upload_url: ${{ steps.create_release.outputs.upload_url }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Create Release
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: Release ${{ github.ref }}
+          draft: false
+          prerelease: false
+
+  build-and-upload:
+    name: Build and Upload
+    needs: create-release
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            target: x86_64-unknown-linux-gnu
+            artifact: miyabi-linux-x86_64
+            binary: miyabi
+          - os: macos-latest
+            target: x86_64-apple-darwin
+            artifact: miyabi-macos-x86_64
+            binary: miyabi
+          - os: macos-latest
+            target: aarch64-apple-darwin
+            artifact: miyabi-macos-aarch64
+            binary: miyabi
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Build release binary
+        run: cargo build --release --target ${{ matrix.target }}
+
+      - name: Package binary (Unix)
+        if: matrix.os != 'windows-latest'
+        run: |
+          cd target/${{ matrix.target }}/release
+          tar czvf ../../../${{ matrix.artifact }}.tar.gz ${{ matrix.binary }}
+          cd -
+
+      - name: Upload Release Asset
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ needs.create-release.outputs.upload_url }}
+          asset_path: ./${{ matrix.artifact }}.tar.gz
+          asset_name: ${{ matrix.artifact }}.tar.gz
+          asset_content_type: application/gzip