Add additional configuration and utility files

- Add install script and message configuration
- Add settings controller and templates
- Add ESP-NOW message utility
- Update API documentation

src/util/README.md

@@ -0,0 +1,80 @@
+# ESPNow Message Builder
+
+This utility module provides functions to build ESPNow messages according to the LED Driver API specification.
+
+## Usage
+
+### Basic Message Building
+
+```python
+from util.espnow_message import build_message, build_preset_dict, build_select_dict
+
+# Build a message with presets and select
+presets = {
+    "red_blink": build_preset_dict({
+        "pattern": "blink",
+        "colors": ["#FF0000"],
+        "delay": 200,
+        "brightness": 255,
+        "auto": True
+    })
+}
+
+select = build_select_dict({
+    "device1": "red_blink"
+})
+
+message = build_message(presets=presets, select=select)
+# Result: {"v": "1", "presets": {...}, "select": {...}}
+```
+
+### Building Select Messages with Step Synchronization
+
+```python
+from util.espnow_message import build_message, build_select_dict
+
+# Select with step for synchronization
+select = build_select_dict(
+    {"device1": "rainbow_preset", "device2": "rainbow_preset"},
+    step_mapping={"device1": 10, "device2": 10}
+)
+
+message = build_message(select=select)
+# Result: {"v": "1", "select": {"device1": ["rainbow_preset", 10], "device2": ["rainbow_preset", 10]}}
+```
+
+### Converting Presets
+
+```python
+from util.espnow_message import build_preset_dict, build_presets_dict
+
+# Single preset
+preset = build_preset_dict({
+    "name": "my_preset",
+    "pattern": "rainbow",
+    "colors": ["#FF0000", "#00FF00"],  # Can be hex strings or RGB tuples
+    "delay": 100,
+    "brightness": 127,
+    "auto": False,
+    "n1": 2
+})
+
+# Multiple presets
+presets_data = {
+    "preset1": {"pattern": "on", "colors": ["#FF0000"]},
+    "preset2": {"pattern": "blink", "colors": ["#00FF00"]}
+}
+presets = build_presets_dict(presets_data)
+```
+
+## API Specification
+
+See `docs/API.md` for the complete ESPNow API specification.
+
+## Key Features
+
+- **Version Field**: All messages include `"v": "1"` for version tracking
+- **Preset Format**: Presets use hex color strings (`#RRGGBB`), not RGB tuples
+- **Select Format**: Select values are always lists: `["preset_name"]` or `["preset_name", step]`
+- **Color Conversion**: Automatically converts RGB tuples to hex strings
+- **Default Values**: Provides sensible defaults for missing fields