Move _ensure_discord_mock() from module level to _make_adapter() so it
doesn't poison sys.modules for other discord test files. Use
types.ModuleType instead of MagicMock for the mock module to avoid
auto-generated __file__ attribute confusing hasattr checks.
Add BrennerSpear to AUTHOR_MAP.
- Remove double str() normalization in _resolve_channel_prompt since
config bridging already handles numeric YAML key conversion
- Remove dead prompts.get(str(key)) fallback that could never match
after keys were already normalized to strings
- Replace getattr(event, "channel_prompt", None) with direct attribute
access since channel_prompt is a declared dataclass field
- Update test to verify normalization responsibility lives in config bridging
