Fix workflow: use docker runner with act container

.gitea/workflows/build.yaml

@@ -1,4 +1,4 @@
-name: Build and Push Docker Image
+name: Build and Push Outline MCP Docker Image
 
 on:
   push:
@@ -8,28 +8,23 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: docker
+    container:
+      image: catthehacker/ubuntu:act-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
 
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-
-      - name: Login to Container Registry
-        uses: docker/login-action@v3
+      - name: Login to Gitea Container Registry
+        uses: docker/login-action@v2
         with:
           registry: gitea.ext.ben.io
-          username: ${{ secrets.REGISTRY_USERNAME }}
-          password: ${{ secrets.REGISTRY_PASSWORD }}
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.CR_PAT }}
 
-      - name: Build and push
-        uses: docker/build-push-action@v5
+      - name: Build and Push
+        uses: docker/build-push-action@v4
         with:
           context: .
           push: true
-          tags: |
-            gitea.ext.ben.io/b3nw/outline-mcp-custom:latest
-            gitea.ext.ben.io/b3nw/outline-mcp-custom:${{ github.sha }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          tags: gitea.ext.ben.io/${{ gitea.repository }}:latest