fix(cache): inline config via compose configs to avoid bind-mount path issue

Coolify's docker compose workdir doesn't always resolve ./config.yaml,
so Docker silently created the mount target as a directory, breaking
runner startup with 'is a directory'. Embed the config in the compose
file via the configs: top-level key — no external file dependency.

config.yaml

@@ -1,8 +0,0 @@
-cache:
-  enabled: true
-  dir: "/data/cache"
-  host: "host.docker.internal"
-  port: 42951
-
-container:
-  options: "--add-host=host.docker.internal:host-gateway"

docker-compose.yml

@@ -12,7 +12,21 @@ services:
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
       - runner_data:/data
-      - ./config.yaml:/config/config.yaml:ro
+    configs:
+      - source: runner_config
+        target: /config/config.yaml
+
+configs:
+  runner_config:
+    content: |
+      cache:
+        enabled: true
+        dir: "/data/cache"
+        host: "host.docker.internal"
+        port: 42951
+
+      container:
+        options: "--add-host=host.docker.internal:host-gateway"
 
 volumes:
   runner_data: