Render API doc markdown as native RST in docstrings

Regenerated service docstrings with genkit's new docfmt renderer, which
parses spec descriptions as CommonMark and emits Sphinx-native RST
instead of leaking raw markdown:

- inline backticks -> ``double-backtick`` literals
- fenced code examples -> .. code-block:: directives
- markdown links -> anonymous RST hyperlinks
- bullet/numbered lists -> proper RST lists (previously broken by
  word-wrap, leaving list markers dangling mid-line)
- stray lone list markers (proto-comment artifacts) are dropped instead
  of rendering an empty list

Generated from the same OpenAPI spec the SDK is current with, so the
diff is docstring-only: code is AST-identical to main for all 33 files.
Formatted with the repo's pinned ruff 0.5.6 (make fmt equivalent).

Co-authored-by: Isaac

Author: tanmay-db