fix: remove image tag and version to fix local build

Having both build: and image: caused Docker Compose to attempt a registry
pull before building locally. Drop image: so it always builds from source.
Remove obsolete version: field.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -1,6 +1,4 @@
-# F2B Control Center — edit values below, then: docker-compose up -d
-
-version: "3.9"
+# F2B Control Center — edit values below, then: docker compose up -d
 
 services:
 
@@ -18,7 +16,6 @@ services:
 
   f2b-control-center:
     build: .
-    image: f2b-control-center:latest
     container_name: f2b-control-center
     restart: unless-stopped
     depends_on: