Add idle auto-shutdown configuration to deployment

- IDLE_TIMEOUT_MINUTES env var (default 30 min)
- restart: no policy so container stays stopped
- Optional wakeup service for auto-restart
- Document three restart options in readme

deploy/.env.example

@@ -0,0 +1,8 @@
+# Cloudflare Tunnel token
+# Get this from: Cloudflare Zero Trust > Networks > Tunnels > Create > Docker
+CLOUDFLARE_TUNNEL_TOKEN=your-tunnel-token-here
+
+# Idle auto-shutdown (minutes)
+# App exits after this many minutes with no active viewers
+# Set to 0 to disable (app runs forever)
+IDLE_TIMEOUT_MINUTES=30