Add Gitea Actions CI/CD and use private registry

Add CI workflow mirroring celery pipeline: SSH to deploy server,
git pull, build and push to registry, deploy docker stack.
Update docker-compose to pull l2-server from registry.rose-ash.com:5000.

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

docker-compose.yml

@@ -16,6 +16,10 @@ services:
       interval: 5s
       timeout: 5s
       retries: 5
+    deploy:
+      placement:
+        constraints:
+          - node.labels.gpu != true
 
   ipfs:
     image: ipfs/kubo:latest
@@ -31,9 +35,12 @@ services:
       replicas: 1
       restart_policy:
         condition: on-failure
+      placement:
+        constraints:
+          - node.labels.gpu != true
 
   l2-server:
-    image: git.rose-ash.com/art-dag/l2-server:latest
+    image: registry.rose-ash.com:5000/l2-server:latest
     env_file:
       - .env
     environment:
@@ -55,6 +62,9 @@ services:
       replicas: 1
       restart_policy:
         condition: on-failure
+      placement:
+        constraints:
+          - node.labels.gpu != true
 
 volumes:
   l2_data: