Add GitHub Actions CI workflow

Build release binaries for linux-x86_64, linux-arm64, and macos-arm64.
Run clippy, rustfmt, and tests on every push/PR. Create GitHub releases
on version tags.

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

Author: piscisaureus

.github/workflows/ci.yml

@@ -0,0 +1,92 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  lint:
+    name: Lint & Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy, rustfmt
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo fmt --check
+      - run: cargo clippy -- -D warnings
+
+  test:
+    name: Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo test
+
+  build:
+    name: Build (${{ matrix.name }})
+    needs: [lint, test]
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      matrix:
+        include:
+          - name: linux-x86_64
+            runner: ubuntu-latest
+            target: x86_64-unknown-linux-gnu
+            artifact: ptywrap-linux-x86_64
+          - name: linux-arm64
+            runner: ubuntu-24.04-arm
+            target: aarch64-unknown-linux-gnu
+            artifact: ptywrap-linux-arm64
+          - name: macos-arm64
+            runner: macos-14
+            target: aarch64-apple-darwin
+            artifact: ptywrap-macos-arm64
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+        with:
+          key: ${{ matrix.target }}
+      - run: cargo build --release
+      - uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.artifact }}
+          path: target/release/ptywrap
+
+  release:
+    name: Release
+    if: startsWith(github.ref, 'refs/tags/v')
+    needs: [build]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          path: artifacts
+
+      - name: Prepare release assets
+        run: |
+          for dir in artifacts/ptywrap-*; do
+            name=$(basename "$dir")
+            chmod +x "$dir/ptywrap"
+            tar -czf "${name}.tar.gz" -C "$dir" ptywrap
+            shasum -a 256 "${name}.tar.gz" >> checksums.txt
+          done
+
+      - uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            ptywrap-*.tar.gz
+            checksums.txt
+          generate_release_notes: true