Address review feedback (#71): cover the event-introspection paths that
previously only had method-side tests.
- impl_header_parser test: assert metadata.json events[].description is
parsed; new documented_events fixture asserts `///` doc-comment
capture on a logos_events: block (multi-line joined with \n,
adjacent-only, plain // ignored).
- lidl_gen_provider test: assert the generated dispatch contains
getEvents() emitting each event's name/signature/parameters and an
escaped description, and that events carry no returnType/isInvokable.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>