Add .env support for transport and sound device configuration

- Add python-dotenv support to control_server.py and sound.py
- Load TRANSPORT from environment variable (default: spi)
- Load AUDIO_INPUT_DEVICE from environment variable (default: 7)
- Load all port configurations from environment variables
- Update .env.example with comprehensive configuration options
- Create .env file with sensible defaults for Pi
- Transport, sound device, and network settings now configurable via .env

.env.example

@@ -1,5 +1,8 @@
 # Lighting Controller Configuration
 
+# ==============================
+# WebSocket Configuration
+# ==============================
 # WebSocket URI for the control server
 # Used by UI client and test scripts to connect to the control server
 #
@@ -11,3 +14,27 @@ CONTROL_SERVER_URI=ws://10.42.0.1:8765
 #
 # For custom IP (if your Pi has a different address):
 # CONTROL_SERVER_URI=ws://YOUR_PI_IP:8765
+
+# Control server WebSocket port
+CONTROL_SERVER_PORT=8765
+
+# ==============================
+# Transport Configuration
+# ==============================
+# Transport method for LED communication
+# Options: spi, websocket
+TRANSPORT=spi
+
+# ==============================
+# Sound Detection Configuration
+# ==============================
+# Audio input device index (use sound.py to list available devices)
+AUDIO_INPUT_DEVICE=7
+
+# MIDI TCP configuration
+MIDI_TCP_HOST=127.0.0.1
+MIDI_TCP_PORT=65432
+
+# Sound control server configuration
+SOUND_CONTROL_HOST=127.0.0.1
+SOUND_CONTROL_PORT=65433