Add CI workflow to publish Docker image on tag

Builds and pushes to registry.samson.media on any version tag,
tagged with both the version and latest.

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

.gitea/workflows/publish.yml

@@ -0,0 +1,41 @@
+name: Publish Image
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+concurrency:
+  group: publish
+  cancel-in-progress: false
+
+jobs:
+  publish:
+    runs-on: self-hosted
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Type check
+        run: npx tsc --noEmit
+
+      - name: Extract tag
+        id: tag
+        run: echo "version=${GITHUB_REF_NAME}" >> "$GITHUB_OUTPUT"
+
+      - name: Log in to registry
+        run: echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login registry.samson.media -u "${{ secrets.REGISTRY_USERNAME }}" --password-stdin
+
+      - name: Build and push
+        run: |
+          IMAGE=registry.samson.media/sdlc-orchestrator
+          docker build -t "$IMAGE:${{ steps.tag.outputs.version }}" -t "$IMAGE:latest" .
+          docker push "$IMAGE:${{ steps.tag.outputs.version }}"
+          docker push "$IMAGE:latest"