Build a Map<string, ReviewComment[]> once in ReviewTab and thread it
down through DiffViewer → FileCard → HunkRows, replacing O(n) filter
calls with O(1) map lookups. With 200 comments and 5000 diff lines,
this reduces ~1M iterations per render cycle to ~5K.
Key: "${filePath}:${lineNumber}:${lineType}" for line-level comments,
"${filePath}:file" for file-level (lineNumber === null) comments.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
ec86b62d8d