Correct module paths and accessor usage in the generator to ensure
generated code builds. Add a test that verifies this by compiling the
generated code in a temporary project.
Resolve `Result` ambiguity and lifetime issues in generated services.
Use `file_stem` for proto filenames. Make `StatusBody` public in
`roto-tonic` and update the `hello_world` build process.
Update map_type_to_rust_accessor to provide default values for each
type, which are used to generate helper methods that return a default
value when a field is missing.
Generate `which_<oneof>` methods and corresponding enums to handle
oneof fields in generated messages. Also add `has_<field>` helper
methods for all fields.
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