- Add the servicelink submodule and register POST /rpc for node-to-node file operations.
- Require bearer tokens with the mesh scope and apply rate/body-size limits to RPC calls.
- Map database connectivity failures to the existing 504 database error flow, with JSON responses for API routes.
- Cover the new RPC handlers and database error handling with focused pytest tests.
- Bump the NanoShare package version to 1.21.0.
