Add GitHub mirror README and remove workflows

- Add .github/README.md for GitHub mirror with clear indication this is a read-only mirror
- Remove GitHub Actions workflow since deployments are handled from primary repository
- Direct all contributions to primary repository at git.deco.sh

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

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

.github/README.md

@@ -0,0 +1,52 @@
+# ❄️ Great Lakes Ice Report (Mirror)
+
+> **⚠️ This is a read-only mirror** of the primary repository hosted at https://git.deco.sh/deco/ice
+
+## 🏠 Primary Repository
+
+For the latest code, issues, pull requests, and discussions, please visit:
+
+**→ https://git.deco.sh/deco/ice**
+
+## 📋 About This Project
+
+A community-driven web application for tracking winter road conditions and icy hazards in the Great Lakes region. Reports automatically expire after 48 hours to maintain current information.
+
+### Key Features
+- 🗺️ Interactive map with real-time location tracking
+- 📱 Progressive Web App - works offline
+- 🌐 Internationalization (English & Spanish)
+- 🚫 Works completely without JavaScript
+- 🔒 Privacy-focused with no user tracking
+
+## 🤝 Contributing
+
+Please submit all issues and pull requests to the primary repository at https://git.deco.sh/deco/ice
+
+## 📦 Quick Start
+
+```bash
+# Clone from the primary repository
+git clone https://git.deco.sh/deco/ice.git
+
+# Or if you prefer SSH
+git clone ssh://git@git.deco.sh:deco/ice.git
+
+cd ice
+npm install
+cp .env.example .env
+# Add your Mapbox token to .env
+npm start
+```
+
+## 🔄 Synchronization
+
+This mirror is automatically synchronized with the primary repository. Updates typically appear within minutes of being pushed to the main repository.
+
+## 📄 License
+
+MIT License - see LICENSE file for details
+
+---
+
+**Why self-hosted?** We believe in data ownership and digital sovereignty. By hosting our primary repository on our own infrastructure, we maintain full control over our code and development process while using GitHub as a discovery platform.