Update Mintlify documentation for Phase 2 completion

📚 Documentation updates reflecting REST API completion:

✅ Updated REST API feature page:
- Added Phase 2 completion notice
- Updated features list with current capabilities
- Replaced generic instructions with actual implementation
- Added comprehensive usage examples (cURL, Python, JavaScript)
- Included testing information and interactive docs links

✅ Updated introduction page:
- Changed status from Phase 1 to Phase 2 complete
- Added REST API to component status table
- Updated API accordion with completion status
- Added REST API server card with direct link

✅ Updated quickstart guide:
- Added Step 3: REST API server startup
- Added Step 4: API testing instructions
- Included specific commands and endpoints

🎯 All documentation now accurately reflects Phase 2 completion
📊 Users can follow updated guides to use the functional API

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

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

docs/quickstart.mdx

@@ -32,4 +32,29 @@ Supabase is already running as part of your existing infrastructure on the local
 python test_all_connections.py
 ```
 
-You should see all systems passing.
+You should see all systems passing.
+
+### Step 3: Start the REST API Server ✅
+
+Our Phase 2 implementation provides a production-ready REST API:
+
+```bash
+python start_api.py
+```
+
+The server will start on **http://localhost:8080** with:
+- Interactive documentation at `/docs`
+- Full authentication and rate limiting
+- Comprehensive error handling
+
+### Step 4: Test the API
+
+Run our test suite to verify everything works:
+
+```bash
+# Quick validation test
+python test_api_simple.py
+
+# Comprehensive test suite  
+python test_api.py
+```