Add complete REST API for lighting control

- Migrated from websockets to aiohttp for unified HTTP/WebSocket server
- Added REST endpoints: /api/pattern, /api/parameters, /api/state, /api/tempo/reset
- Implemented color palette API with 8-slot system and selected colors
- First selected color (index 0) is used as primary RGB for patterns
- All operations now available via simple HTTP requests (no WebSocket needed)
- Added comprehensive documentation: FRONTEND_API.md, COLOR_PALETTE_API.md
- Added test scripts: test_rest_api.sh, test_color_patterns.py
- Updated test/test_control_server.py for new /ws WebSocket path
- Configuration persistence via lighting_config.json
- Pattern parameters (n1-n4, brightness, delay) controllable via API
- WebSocket still available at /ws for legacy support

COLOR_API_QUICK_REF.md

@@ -0,0 +1,129 @@
+# Color Palette API - Quick Reference Card
+
+## 🎯 Endpoints
+
+| Method | URL | Purpose |
+|--------|-----|---------|
+| `GET` | `http://10.42.0.1:8765/api/color-palette` | Get current palette |
+| `POST` | `http://10.42.0.1:8765/api/color-palette` | Update palette/selection |
+| `PUT` | `http://10.42.0.1:8765/api/color-palette` | Same as POST |
+
+**Backup:** Same endpoints available on port `8766`
+
+---
+
+## 📦 Data Structure
+
+```javascript
+{
+  palette: [
+    {r: 255, g: 0, b: 0},    // Slot 0
+    {r: 0, g: 255, b: 0},    // Slot 1
+    {r: 0, g: 0, b: 255},    // Slot 2
+    {r: 255, g: 255, b: 0},  // Slot 3
+    {r: 255, g: 0, b: 255},  // Slot 4
+    {r: 0, g: 255, b: 255},  // Slot 5
+    {r: 255, g: 128, b: 0},  // Slot 6
+    {r: 255, g: 255, b: 255} // Slot 7
+  ],
+  selected_indices: [0, 1]   // Active colors
+                             // [0] = Primary RGB for patterns
+                             // [1] = Reserved for future use
+}
+```
+
+---
+
+## 💻 Copy-Paste Code
+
+### Get Palette
+```javascript
+const res = await fetch('http://10.42.0.1:8765/api/color-palette');
+const {palette, selected_indices} = await res.json();
+```
+
+### Update Color (e.g., slot 3 to purple)
+```javascript
+const current = await fetch('http://10.42.0.1:8765/api/color-palette')
+  .then(r => r.json());
+
+const newPalette = [...current.palette];
+newPalette[3] = {r: 128, g: 0, b: 128};
+
+await fetch('http://10.42.0.1:8765/api/color-palette', {
+  method: 'POST',
+  headers: {'Content-Type': 'application/json'},
+  body: JSON.stringify({palette: newPalette})
+});
+```
+
+### Select Colors (e.g., slots 2 and 5)
+```javascript
+await fetch('http://10.42.0.1:8765/api/color-palette', {
+  method: 'POST',
+  headers: {'Content-Type': 'application/json'},
+  body: JSON.stringify({selected_indices: [2, 5]})
+});
+```
+
+---
+
+## 🛠️ Helper Functions
+
+### RGB ↔ Hex Conversion
+```javascript
+const rgbToHex = ({r, g, b}) => 
+  '#' + [r, g, b].map(x => x.toString(16).padStart(2, '0')).join('');
+
+const hexToRgb = (hex) => {
+  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
+  return result ? {
+    r: parseInt(result[1], 16),
+    g: parseInt(result[2], 16),
+    b: parseInt(result[3], 16)
+  } : null;
+};
+```
+
+---
+
+## ✅ Validation Rules
+
+- **8 colors** in palette (exactly)
+- **RGB values** 0-255 (integers)
+- **2 selected indices** (exactly)
+- **Indices** 0-7 (valid range)
+
+---
+
+## 🧪 Test
+
+```bash
+# Get
+curl http://10.42.0.1:8765/api/color-palette | jq
+
+# Update selection
+curl -X POST http://10.42.0.1:8765/api/color-palette \
+  -H "Content-Type: application/json" \
+  -d '{"selected_indices": [0, 2]}'
+
+# Run full test suite
+./test_color_api.sh 10.42.0.1
+```
+
+---
+
+## 📝 Notes
+
+- **First selected color (index 0) is used as the primary RGB for LED patterns**
+- Changes auto-save to `lighting_config.json`
+- Invalid data is ignored (not rejected)
+- Validate client-side before sending
+- WebSocket is at `ws://10.42.0.1:8765/ws` (different path)
+
+---
+
+## 📚 Full Docs
+
+See `COLOR_PALETTE_API.md` for complete documentation
+