Report removed files in baseline comparisons

[rogerchappel]

Summary

• include files absent from the current scan as explicit removed baseline entries
• render the removed status and prior coverage in text and JSON reports
• cover the misleading +50-point improvement case and document the behavior

Commits

1. test: define removed baseline file reporting — adds the regression contract and extends the structured status type
2. fix: include removed files in baseline comparisons — reconciles unmatched baseline files and renders them
3. docs: explain removed baseline file entries — documents why prior coverage remains visible

Verification

• npm ci
• npm run release:check (audits, typecheck, lint, 90 tests with coverage, CLI smoke, package smoke)
• git diff --check origin/main...HEAD

All three commits are authored and committed by Roger Chappel miscanalysis@gmail.com.

[rogerchappel]

Automated merge note

Triage class: auto-repair

Summary: Report baseline files removed from the current scan, with a focused test/doc update. Repaired the text assertion to tolerate picocolors ANSI formatting.

Checks run: local npm ci and npm run release:check (audit, typecheck, lint, 90 tests, smoke, package smoke); GitHub CI test (20.19.0), test (22), and test (24) all SUCCESS.

Rebased/CI-repaired: CI-repaired in an isolated worktree; no rebase or conflict resolution was required.

Verified head SHA: 497b763fd7c427d9e2d40c8868af050f69a03439