• Merge pull request #525 from kaitranntt/kai/feat/518-cursor-protobuf-executor
• fix(cursor): tighten rate limit detection string matching
• fix(cursor): address fourth-round review feedback for protobuf module
• fix(cursor): address third-round review feedback for protobuf module
• fix(cursor): address second-round review feedback for protobuf module
• fix(cursor): address remaining LOW review items in protobuf module
• fix(cursor): address code review feedback (attempt 1/5)
• fix(cursor): address code review edge cases in protobuf and executor
• feat(cursor): add core protobuf encoder/decoder and executor