Initial commit: WLED Screen Controller with FastAPI server and Home Assistant integration

This is a complete WLED ambient lighting controller that captures screen border pixels
and sends them to WLED devices for immersive ambient lighting effects.

## Server Features:
- FastAPI-based REST API with 17+ endpoints
- Real-time screen capture with multi-monitor support
- Advanced LED calibration system with visual GUI
- API key authentication with labeled tokens
- Per-device brightness control (0-100%)
- Configurable FPS (1-60), border width, and color correction
- Persistent device storage (JSON-based)
- Comprehensive Web UI with dark/light themes
- Docker support with docker-compose
- Windows monitor name detection via WMI (shows "LG ULTRAWIDE" etc.)

## Web UI Features:
- Device management (add, configure, remove WLED devices)
- Real-time status monitoring with FPS metrics
- Settings modal for device configuration
- Visual calibration GUI with edge testing
- Brightness slider per device
- Display selection with friendly monitor names
- Token-based authentication with login/logout
- Responsive button layout

## Calibration System:
- Support for any LED strip layout (clockwise/counterclockwise)
- 4 starting position options (corners)
- Per-edge LED count configuration
- Visual preview with starting position indicator
- Test buttons to light up individual edges
- Smart LED ordering based on start position and direction

## Home Assistant Integration:
- Custom HACS integration
- Switch entities for processing control
- Sensor entities for status and FPS
- Select entities for display selection
- Config flow for easy setup
- Auto-discovery of devices from server

## Technical Stack:
- Python 3.11+
- FastAPI + uvicorn
- mss (screen capture)
- httpx (async WLED client)
- Pydantic (validation)
- WMI (Windows monitor detection)
- Structlog (logging)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

custom_components/wled_screen_controller/const.py

@@ -0,0 +1,23 @@
+"""Constants for the WLED Screen Controller integration."""
+
+DOMAIN = "wled_screen_controller"
+
+# Configuration
+CONF_SERVER_URL = "server_url"
+
+# Default values
+DEFAULT_SCAN_INTERVAL = 10  # seconds
+DEFAULT_TIMEOUT = 10  # seconds
+
+# Attributes
+ATTR_DEVICE_ID = "device_id"
+ATTR_FPS_ACTUAL = "fps_actual"
+ATTR_FPS_TARGET = "fps_target"
+ATTR_DISPLAY_INDEX = "display_index"
+ATTR_FRAMES_PROCESSED = "frames_processed"
+ATTR_ERRORS_COUNT = "errors_count"
+ATTR_UPTIME = "uptime_seconds"
+
+# Services
+SERVICE_START_PROCESSING = "start_processing"
+SERVICE_STOP_PROCESSING = "stop_processing"