Migrate CI workflow from GitHub Actions to Gitea Actions

Moves workflow to .gitea/workflows/ and updates container registry
from ghcr.io to git.necloud.us using REGISTRY_USER/REGISTRY_TOKEN secrets.

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

.gitea/workflows/publish-container.yml

@@ -6,10 +6,6 @@ on:
       - main
   workflow_dispatch:
 
-permissions:
-  contents: read
-  packages: write
-
 jobs:
   publish:
     runs-on: ubuntu-latest
@@ -21,18 +17,18 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
-      - name: Log in to GitHub Container Registry
+      - name: Log in to Gitea Container Registry
         uses: docker/login-action@v3
         with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          registry: git.necloud.us
+          username: ${{ secrets.REGISTRY_USER }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
 
       - name: Extract image metadata
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ghcr.io/nmemmert/weather
+          images: git.necloud.us/nate/weather
           tags: |
             type=raw,value=latest
             type=sha