feat: Default to OCR scanner, auto-start camera, hide viewport after capture

- Default add-asset mode changed from barcode to OCR
- Auto-start OCR camera when switching to OCR mode or Add Asset tab
- Camera viewport hidden entirely after photo capture (no placeholder showing)
- Retake button added to all OCR result states (found, not-found, error)
- 'Retake' resets UI and re-starts camera for a new photo

restart_server.sh

@@ -1,16 +1,10 @@
 #!/bin/bash
-# Restart canteen-asset-tracker server
 cd /home/oplabs/projects/canteen-asset-tracker
-
-# Kill existing server
-pkill -f "python.*server.py" 2>/dev/null || true
+pkill -f "uvicorn.*server:app.*8901" 2>/dev/null || true
 sleep 1
-
-# Activate venv and start
-source .venv/bin/activate
-nohup python server.py > /tmp/canteen-server.log 2>&1 &
-echo "Server PID: $!"
-sleep 3
-
-# Check health
-curl -s http://localhost:8901/health 2>/dev/null || curl -s http://localhost:8900/health 2>/dev/null || echo "Health check failed"
+python -m uvicorn server:app --host 0.0.0.0 --port 8901 \
+  --ssl-keyfile key.pem --ssl-certfile cert.pem --log-level info \
+  > /tmp/canteen-server.log 2>&1 &
+echo "PID=$!"
+sleep 2
+curl -sk https://localhost:8901/health 2>/dev/null