Add .env file support for UI client configuration

- Use python-dotenv to load environment variables
- Add CONTROL_SERVER_URI environment variable for WebSocket connection
- Create .env.example with configuration examples
- Update Pipfile to include python-dotenv dependency
- Allows easy configuration for running UI on desktop pointing to Pi

.env.example

@@ -0,0 +1,9 @@
+# Lighting Controller UI Client Configuration
+
+# WebSocket URI for the control server
+# For local development (running UI on same machine as control server):
+CONTROL_SERVER_URI=ws://localhost:8765
+
+# For remote connection (running UI on desktop, control server on Pi):
+# Replace with your Raspberry Pi's IP address
+# CONTROL_SERVER_URI=ws://10.1.1.117:8765

Pipfile

@@ -13,6 +13,7 @@ python-rtmidi = "*"
 pyaudio = "*"
 aubio = "*"
 websocket-client = "*"
+python-dotenv = "*"
 
 [dev-packages]
 

src/ui_client.py

@@ -15,10 +15,14 @@ import logging
 from async_tkinter_loop import async_handler, async_mainloop
 import websockets
 import websocket
+from dotenv import load_dotenv
+
+# Load environment variables from .env file
+load_dotenv()
 
 # Configuration
 CONFIG_FILE = "config.json"
-CONTROL_SERVER_URI = "ws://localhost:8765"
+CONTROL_SERVER_URI = os.getenv("CONTROL_SERVER_URI", "ws://localhost:8765")
 
 # Dark theme colors
 bg_color = "#2e2e2e"