Hub runtime: allocate port 8788, add Go skeleton and Docker deployment

Co-Authored-By: Paperclip <noreply@paperclip.ing>

docker-compose.yml

@@ -0,0 +1,21 @@
+services:
+  hub:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    image: central-ai-hub:local
+    container_name: hub
+    restart: unless-stopped
+    ports:
+      - "8788:8788"
+    environment:
+      HUB_PORT: "8788"
+    # Secrets are never hard-coded. The Hub keys (HUB_TOKEN_*, OMNIROUTE_API_KEY)
+    # come from ~/.config/environment.d/10-secrets.conf. Add only the keys the
+    # running routes need, when they land (AUD-49+).
+    healthcheck:
+      test: ["CMD", "/hub", "-healthcheck"]
+      interval: 30s
+      timeout: 3s
+      retries: 3
+      start_period: 5s