Update imports to use `roto_tonic` instead of `crate` for BufferPool
and StatusBody. Remove the broad replacement of `crate` with `roto`
and add error output to `test_map_build.rs`.
Use absolute paths for temporary project directories and dependencies
to improve reliability. Update the generated Cargo.toml with additional
dependencies and remove the offline flag from cargo build.
Update the generator to detect map fields and use MapFieldIterator.
Implement MapFieldIterator in the runtime to handle key-value pair
extraction and add write_map_entry to ProtoBuilder. Add tests to
verify that map-bearing messages generate and compile correctly.
charles