fit-review

Dispatch one sub-agent with git diff <ref>...HEAD (<ref> the user's, else main) and this brief:

"Overfit is code, a comment, or a doc shaped around this change instead of the scope it lives in. First read outside the diff: each changed file's module and its nearest AGENTS.md, README, design/ note, and ADR. Per changed file, report whether the change fits the module's design or bends it (a special case, flag, or call-site patch the design should absorb). Per comment or doc change, report what sits above the document's scope: narrating the PR, restating a neighbouring doc, detail the bigger picture does not need. Recommend a trim for every finding; less is better. Under 400 words."