chore: production docker + compose for LAN deployment

README.md

@@ -107,6 +107,49 @@ Open display pages:
 
 - `http://<server-ip>:5000/display/<public_id>`
 
+## Docker (production-ready)
+
+This repo includes a `Dockerfile` and `docker-compose.yml` suitable for LAN deployments.
+
+### Docker networking for LAN + UDP triggers
+
+SyncPlayer listens on **UDP ports configured per Event**.
+
+Docker has two workable strategies:
+
+1) **Publish a UDP port range** (works on Docker Desktop + Linux)
+   - The default `syncplayer` service publishes `7000-7999/udp`.
+   - Keep your Event UDP ports within that range.
+
+2) **Host networking** (Linux only)
+   - Use `docker compose --profile hostnet up -d --build`
+   - Dynamic UDP ports work without pre-declaring a range.
+   - Discovery/casting protocols (mDNS/SSDP/etc.) also work best here.
+
+In both cases HTTP + Socket.IO is reachable at `http://<host-ip>:5000`.
+
+### Run
+
+```bash
+docker compose up -d --build
+```
+
+Data is persisted in `./data/` on the host:
+
+- `./data/syncplayer.db`
+- `./data/media/` (uploaded videos + idle image)
+- `./data/logs/system.log`
+
+Then open:
+
+- Admin: `http://<host-ip>:5000/admin/`
+- Displays: `http://<host-ip>:5000/display/<public_id>`
+
+### Notes
+
+- Default Gunicorn configuration runs **1 worker** to avoid starting multiple UDP listeners.
+- Change `SECRET_KEY` in `docker-compose.yml` for real deployments.
+
 ## UDP trigger
 
 Configure UDP Port + UDP Payload on an Event in the admin UI. The UDP listener binds ports automatically (refreshes config every 5s).