ci: add release workflow for Windows, macOS, and Linux binaries

- Build standalone executables with PyInstaller
- Auto-create GitHub release on version tag push
- Release includes binaries for all platforms

.github/workflows/release.yml

@@ -0,0 +1,82 @@
+name: Build & Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: Build ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        include:
+          - os: ubuntu-latest
+            artifact_name: genpass-linux
+            asset_name: genpass-linux
+          - os: windows-latest
+            artifact_name: genpass-windows.exe
+            asset_name: genpass-windows.exe
+          - os: macos-latest
+            artifact_name: genpass-macos
+            asset_name: genpass-macos
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pyinstaller
+          pip install -e .
+
+      - name: Build executable with PyInstaller
+        run: |
+          pyinstaller --onefile --name ${{ matrix.artifact_name }} genpass/cli.py
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.artifact_name }}
+          path: dist/${{ matrix.artifact_name }}${{ matrix.os == 'windows-latest' && '.exe' || '' }}
+
+  release:
+    name: Create 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: Prepare release assets
+        run: |
+          cd artifacts
+          ls -R
+          mv genpass-linux/genpass-linux genpass-linux
+          mv genpass-windows.exe/genpass-windows.exe genpass-windows.exe
+          mv genpass-macos/genpass-macos genpass-macos
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v1
+        with:
+          files: |
+            artifacts/genpass-linux
+            artifacts/genpass-windows.exe
+            artifacts/genpass-macos
+          generate_release_notes: true
+          draft: true