feat: Add Gitea Actions CI/CD for Docker image build

- Add .gitea/workflows/build.yml for automated builds on tag push
- Update docker-compose.yml to pull from Gitea Registry
- Add docker-compose.build.yml for local development builds

Build triggers on tags matching 'v*' (e.g., v1.0.0)
Images pushed to gitea.likegears.com/likegears/material_texture

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -0,0 +1,38 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: catthehacker/ubuntu:act-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: gitea.likegears.com
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Extract version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT
+
+      - name: Build and Push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: |
+            gitea.likegears.com/likegears/material_texture:${{ steps.version.outputs.VERSION }}
+            gitea.likegears.com/likegears/material_texture:latest