wiki: document the CI gate — clippy now gates on this repo Written from the diff rather than from the central ai-meta log, per agents/rules/change-documentation.md: a reader opening this repo should get what changed HERE, not the cross-repo narrative. Records the guard and what it exists to prevent, which is the thing most likely to be deleted as noise later: why each clippy -A carries its reason, and (where applicable) whether the toolchain is pinned -- an unpinned lint set means main can go red with no code change. Refs noetl/ai-meta#374 Refs noetl/ai-meta#378 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>