ci: push Docker images to Gitea container registry on release tags

- Update release workflow to build and push to git.cqre.net/cqrenet/aoc-backend
- Update docker-compose.yml to pull from Gitea registry

.gitea/workflows/release.yml

@@ -6,15 +6,17 @@ on:
       - "v*"
 
 jobs:
-  build:
+  build-and-push:
     runs-on: ubuntu-latest
-
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Build Docker image
-        run: docker build ./backend --tag aoc-backend:${{ gitea.ref_name }}
+      - name: Log in to Gitea Container Registry
+        run: echo "${{ secrets.GITEA_TOKEN }}" | docker login git.cqre.net -u ${{ gitea.actor }} --password-stdin
 
-      - name: Verify image exists
-        run: docker images | grep aoc-backend
+      - name: Build Docker image
+        run: docker build ./backend --tag git.cqre.net/cqrenet/aoc-backend:${{ gitea.ref_name }}
+
+      - name: Push Docker image
+        run: docker push git.cqre.net/cqrenet/aoc-backend:${{ gitea.ref_name }}