Clean up server architecture for multi-instance deployment

- Remove main_cycling.py, main_multi.py, main_release.py (single main.py is canonical)
- Update setup.sh to read SERVICE_NAME and PORT from .env
- Update env.example with SERVICE_NAME and PORT for multi-instance support
- Fix server-csi to try rpicam-still before libcamera-still (Debian Trixie)

Deploy pattern: clone repo twice, configure each .env, run setup.sh
Each instance gets its own systemd service and install directory.

server/env.example

@@ -6,12 +6,20 @@
 # API Key for authentication (generate with: python3 -c 'import secrets; print(secrets.token_urlsafe(32))')
 API_KEY=your-secret-key-here
 
-# Camera identifier (used in events)
+# Camera identifier (used in events and API responses)
 CAMERA_ID=basement
 
+# ============ Service Settings ============
+
+# Service name for systemd (allows multiple instances)
+SERVICE_NAME=vixy-vision-basement
+
+# Port to run on (each instance needs unique port)
+PORT=8443
+
 # ============ Camera Settings ============
 
-# Camera device index (0 = first USB camera)
+# Camera device index (0 = /dev/video0, 2 = /dev/video2, etc.)
 CAMERA_INDEX=0
 
 # Resolution (camera will use closest supported)
@@ -40,8 +48,8 @@ MOTION_INTERVAL=0.5
 
 # ============ Event Collector ============
 
-# URL to POST motion events to (on Mac mini)
-COLLECTOR_URL=http://192.168.1.50:8780/events
+# URL to POST motion events to (collector on Mac mini)
+COLLECTOR_URL=http://macmini.local:8780/events
 
 # API key for collector (optional)
 COLLECTOR_API_KEY=