fix: bound and validate review titles

[Xiangyu7]

Summary

• require REVIEW headers and titles to remain on a single line
• normalize review titles and cap them at 120 characters before storing them
• tell the review-suggestion model to keep titles within the same limit
• add a regression test covering a malformed header followed by a valid review block

Root cause

The previous review-block regular expression allowed the title capture to cross line boundaries. If a model omitted the closing --- on a REVIEW header, the parser could consume the description and later review blocks as one oversized title.

The updated parser rejects that malformed header instead of swallowing subsequent valid blocks. Full review explanations remain in the description; only the title is bounded.

Impact

Malformed model output can no longer turn an entire REVIEW payload into a title or contaminate later valid review suggestions. This also gives persistence layers a predictable title size without discarding the detailed explanation.

Validation

• npm run test:mocks — 118 test files, 1722 tests passed
• TypeScript build/typecheck passed