Apply a review tip

Report review spec §11. P1 applies a completeness tip whose fix is an answer: the body's answer is validated and written exactly as PATCH /reporting-profile/{year} writes it (for fix.year, in the request's workspace, source user), and the tip is marked applied in the same transaction. The version itself is frozen: updateOffered is true and the client offers "Update report". Applying an applied tip answers 200 unchanged. 409 REPORT_REVIEW_APPLY_REJECTED for a tip whose fix is a link, REPORT_REVIEW_FINDING_CLOSED for a dismissed tip, WORKSPACE_SCOPE_UNSUPPORTED in a workspace that keeps no answers of its own, PROFILE_CHANGED when the answer kept changing while it was being saved (retry); 400 VALIDATION_ERROR for an answer the question does not take. A wording tip is applied with no body (or {}): its sentence is replaced by the stored rewrite (or removed, for an empty rewrite, with the paragraph's other open tips re-anchored to their sentences) through the manual edit's own save (a published version is copied into a new draft version, its tips carried), and the response's report is the version written. 409 REPORT_REVIEW_VERSION_SUPERSEDED when the version is no longer the report's current draft version, REPORT_REVIEW_FINDING_OUT_OF_DATE when its sentence changed, REPORT_REVIEW_APPLY_REJECTED when the edit is refused; 400 VALIDATION_ERROR for an answer on a wording tip or no answer on a completeness tip. Needs report.edit_draft, and report.create when an answer is sent.