Release image builds were relying on docker/build-push-action's implicit context resolution, which can fall back to a git URL in release runs. This change makes the reusable action always build from the checked-out workspace so sidecar and EPP image builds use a stable local context.

• Build context

  • Set context: . in .github/actions/docker-build-and-push/action.yml.
  • Removes reliance on BuildKit inferring the source as https://github.com/llm-d/llm-d-router.git#<sha> during release execution.

• Release image behavior preserved

  • Keeps existing image tags, cache configuration, build args, and platform selection unchanged.
  • Applies uniformly to both no-push tarball exports and pushed multi-arch builds because both paths use the same reusable action.

- name: Build image
  uses: docker/build-push-action@v6
  with:
    context: .
    file: ${{ inputs.docker-file }}
    push: ${{ inputs.push == 'true' }}