M08-L02 exercise

Starting checkpoint: CP08 to CP09. Figures: SS17-02.

Implement the four planned slices with bounded commits or reviewed diffs. Demonstrate equality entry, then complete clearing, parser, integration, and regression checks. Submit the requirement-to-change map, source, tests, and actual receipts. If a generated patch changes unrelated features, preserve useful work and narrow it before proceeding.

Record source identity, changed files, exact commands, actual outcomes, and open limitations. Preserve the original exercise copy and review the final diff. Expected results are criteria, not evidence of execution.