rust-junosmcp v0.27.4

Added

• Official MCP Registry listing. The image now carries
  io.modelcontextprotocol.server.name="io.github.mechubsec/rustjunosmcp",
  which the registry uses to verify image ownership, and the repo ships a
  server.json describing the documented stdio container invocation.

Changed

• Dependency and CI updates: distroless cc-debian13 base image digest,
  cargo-minor-patch group, and pinned mecmcp reusable workflows.
• Docs: stdio container invocation and fwconfigsanitizer references.