add: tsdown workflow

.github/workflows/tsdown.yml

@@ -0,0 +1,50 @@
+name: tsdown
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Generate tsdown config
+        run: |
+          cat > tsdown.config.ts << 'EOL'
+          import { defineConfig } from 'tsdown'
+
+          export default defineConfig({
+            entry: ['./src'],
+            format: ['esm'],
+            clean: true,
+            dts: true,
+            minify: true,
+            sourcemap: true,
+            external: [],
+            platform: 'node',
+            treeshake: true
+          })
+          EOL
+
+      - name: Install tsdown and types
+        run: npm install --save-dev tsdown @types/node
+
+      - name: Build with tsdown
+        run: npx tsdown build
+
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/
+          retention-days: 5 

README.md

@@ -25,6 +25,49 @@ jobs:
       DISCORD_WEBHOOK: ${{ secrets.DISCORD_WEBHOOK_MERGEBOT }}
 ```
 
+## tsdown
+
+This workflow provides a standardized build process for TypeScript libraries using tsdown. It includes:
+
+- Automatic building on push and pull requests
+- Node.js setup with caching
+- Automatic tsdown configuration generation
+- Build artifact uploads
+
+### Usage
+
+Add the following to your repository's workflow:
+
+```yml
+name: Build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    uses: bombshell-dev/automation/.github/workflows/tsdown.yml@main
+```
+
+The workflow will automatically:
+1. Generate a standard tsdown configuration
+2. Install necessary dependencies (tsdown and @types/node)
+3. Build your TypeScript project
+4. Upload the build artifacts
+
+The generated configuration includes:
+- ESM output format
+- TypeScript declaration file generation
+- Source maps
+- Minification
+- Node.js platform targeting
+- Tree shaking optimization
+
+If you need to customize the configuration, you can create your own `tsdown.config.ts` file in your project root, and the workflow will use that instead of generating one.
+
 ## Acknowledgements
 
 This repository borrows heavily from [`withastro/automation`](https://github.com/withastro/automation), published under the MIT License—Copyright (c) 2023 Astro.