add CONTRIBUTING.md

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

CONTRIBUTING.md

@@ -0,0 +1,14 @@
+# Contributing
+
+Thank you for your interest in contributing to the Start9 website.
+
+## Development
+
+1. Clone the repository
+2. Install dependencies: `npm install`
+3. Start the dev server: `npm start`
+4. Open http://localhost:8080
+
+## Deployment
+
+Pushes to `master` automatically build and deploy via GitHub Actions.