fix(doc): compose file in README

Without a docker compose the recommended install part of the documentation will not work at all

README.md

@@ -137,12 +137,55 @@ To install the **Akkudoktor-EOS** add-on in Home Assistant:
 
 ### Docker (Recommended)
 
+1. **create docker compose file**:
+
+```yaml
+services:
+  eos:
+    image: akkudoktor/eos:latest
+    container_name: akkudoktoreos
+    restart: unless-stopped
+    environment:
+      - OPENBLAS_NUM_THREADS=1
+      - OMP_NUM_THREADS=1
+      - MKL_NUM_THREADS=1
+      - EOS_SERVER__HOST=0.0.0.0
+      - EOS_SERVER__PORT=8503
+      - EOS_SERVER__EOSDASH_HOST=0.0.0.0
+      - EOS_SERVER__EOSDASH_PORT=8504
+      # Change this to a random secret, e.g. output of: openssl rand -hex 32
+      - EOS_SERVER__EOSDASH_SESSKEY=change-me
+    ports:
+      - "8503:8503"   # EOS API
+      - "8504:8504"   # EOSdash
+    volumes:
+      - ./data:/data
+```
+
+2. **create a .env file with the secret**:
+
+```bash
+echo "EOS_SESSKEY=$(openssl rand -hex 16)" > .env
+```
+
+3. **pull image and start**:
+
 ```bash
 docker pull akkudoktor/eos:latest
 docker compose up -d
 ```
 
-Access the API at `http://localhost:8503` (docs at `http://localhost:8503/docs`)
+4. **Access EOS**:
+
+   - API: http://localhost:8503
+   - API docs: http://localhost:8503/docs
+   - EOSdash: http://localhost:8504
+
+Configuration and data are stored in `./data`.
+
+> **Note:** The `docker-compose.yaml` in the repository root is intended for development
+> (it builds the image locally and relies on the repository's `.env`). Use the file above
+> if you only want to run the published image.
 
 ### From Source
 

docker-compose.ps1

@@ -34,4 +34,4 @@ $env:DOCKER_COMPOSE_DATA_DIR = $DockerComposeDataDir
 
 Write-Host "EOS data dir: '$env:DOCKER_COMPOSE_DATA_DIR'"
 
-docker compose -f docker-compose.yml up -d
+docker compose -f docker-compose.yaml up -d