Initial commit: Camera Viewer with Frigate alerts

Features:
- 8-camera WebRTC grid using go2rtc
- MQTT subscription to Frigate events
- Auto-fullscreen on person detection (Front_Porch)
- SSE for real-time browser updates
- Touch-friendly tablet interface
- Wake lock to keep screen on
- Auto-dismiss after 30 seconds

run.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+cd /opt/camera-viewer
+source venv/bin/activate
+uvicorn app.main:app --host 0.0.0.0 --port 8080 --reload