build(compose): adapt compose file for Coolify deployment

Drop container_name and the local image tag, which conflict with Coolify's own container and image naming, and expose the configured app port without publishing it. Document the Coolify file storage for config.yml.

README.md

@@ -81,6 +81,8 @@ cp config.example.yml config.yml
 docker compose up -d --build
 ```
 
+`compose.yml` also deploys on Coolify with the Docker Compose build pack (compose file `/compose.yml`). Coolify turns the `./config.yml` bind mount into an editable file storage; paste your config there. Keep the real `config.yml` out of git, since it holds datastore credentials.
+
 ## Quick start (Docker)
 
 ```bash

compose.yml

@@ -2,8 +2,21 @@ services:
   keepalive:
     build:
       context: .
-    image: keepalive:local
-    container_name: keepalive
     restart: unless-stopped
+    # keepalive reads no environment variables: every setting lives in the
+    # config file below. Coolify still injects its dashboard variables through
+    # its generated .env, so nothing needs declaring here.
+    #
+    # The app has no HTTP server. `expose` only mirrors the port the Coolify
+    # app was configured with; it publishes nothing on the host, and nothing
+    # answers on it.
+    expose:
+      - "3000"
+    # The app reads /config.yml (see config.go). Coolify turns this bind mount
+    # into an editable file storage; locally, copy config.example.yml to
+    # config.yml first. The real config holds datastore credentials, so never
+    # commit it.
     volumes:
       - ./config.yml:/config.yml:ro
+    # No healthcheck: the distroless image ships no shell or HTTP client to
+    # run one, and the Dockerfile defines none.