fix(ci): upgrade to build-push-action@v6, disable sbom

- Upgrade docker/build-push-action from v5 to v6
- Add sbom: false alongside provenance: false
- Update registry URL to internal domain

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

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

.gitea/workflows/build.yml

@@ -13,16 +13,17 @@ jobs:
       - name: Login to Gitea Registry
         uses: docker/login-action@v3
         with:
-          registry: git.schweitz.net
+          registry: git.schweitz.internal
           username: ${{ secrets.REGISTRY_USER }}
           password: ${{ secrets.REGISTRY_PASSWORD }}
 
       - name: Build and push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           push: true
           provenance: false
+          sbom: false
           tags: |
             git.schweitz.internal/jpmschweitzer/tatlock:latest
             git.schweitz.internal/jpmschweitzer/tatlock:${{ github.ref_name }}