feat(docker): add Docker Hub authentication for CI/CD workflows

- Introduced `docker_hub_token` and `docker_hub_username` secrets for Docker Hub login in CI/CD workflows.
- Updated `.gitea/workflows/ci.yaml`, `.gitea/workflows/cd.yaml`, and `.gitea/workflows/quality.yaml` to utilize these secrets for Docker Hub authentication.
- Enhanced README and releasing documentation to clarify the use of Docker Hub credentials for image mirroring and builds.

.gitea/workflows/cd.yaml

@@ -17,6 +17,8 @@ jobs:
       allow_registry_login: false
     secrets:
       ACTIONS_PAT: ${{ secrets.ACTIONS_PAT }}
+      docker_hub_token: ${{ secrets.docker_hub_token }}
+      docker_hub_username: ${{ secrets.docker_hub_username }}
 
   publish:
     needs: [quality]
@@ -107,6 +109,12 @@ jobs:
           short_sha="$(echo '${{ github.sha }}' | cut -c1-7)"
           echo "short_sha=$short_sha" >> "$GITHUB_OUTPUT"
           echo "build_time=$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> "$GITHUB_OUTPUT"
+      - name: Log in to Docker Hub
+        if: steps.rel.outputs.released == 'true'
+        uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
+        with:
+          username: ${{ secrets.docker_hub_username || gitea.actor }}
+          password: ${{ secrets.docker_hub_token }}
       - name: Log in to Gitea Registry
         if: steps.rel.outputs.released == 'true'
         uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0