chore: remove unused Impeccable project metadata

[sunsunsun-java]

Problem and value

The repository still tracks a stale .impeccable/design.json sidecar even though the project no longer uses Impeccable. Removing it eliminates an unused generated artifact and its maintenance obligation, while a root-anchored ignore rule prevents the sidecar from being recommitted.

Closes #158

Scope

• What changed: removed .impeccable/design.json (140 lines) and added /.impeccable/ to the root .gitignore.
• What deliberately did not change: DESIGN.md, PRODUCT.md, runtime code, schemas, renderers, tests, and release inputs.
• No unrelated changes: confirmed; the PR-specific diff contains one deleted metadata file and one ignore-rule insertion. The branch is updated with current main.

Stability impact

• Compatibility and migration risk: none for Archify runtime or published interfaces; only the unused Impeccable tooling sidecar is removed.
• Renderer, validator, package, or generated-artifact risk: none. The release builder packages only tracked files under archify/.
• Failure behavior and rollback path: restore .impeccable/design.json and remove the ignore rule if Impeccable is adopted again.

Tests run

• cd archify && npm test — 746 tests: 721 passed, 0 failed, 25 skipped.
• git diff --check upstream/main...HEAD — passed.
• git check-ignore --no-index -v .impeccable/design.json — matched root /.impeccable/; nested .impeccable/ remained unaffected.
• scripts/build-zip.sh /tmp/archify-pr160-updated.zip followed by byte comparison — rebuilt archive was byte-identical to archify.zip.

Visual evidence

Not applicable; this is a non-visual repository metadata cleanup.

Generated artifacts

None changed. The removed root-level file and root ignore rule are outside the tracked-only archify/ package input, and the rebuilt archive is byte-identical.

Checklist

• I used a minimal focused change and preserved existing typed JSON behavior unless the issue requires a contract change.
• I ran the relevant targeted tests and npm test in archify/.
• I added or updated a regression test for behavioral changes. Not applicable: this change removes unreferenced tool metadata and changes no behavior.
• I checked generated artifacts and package freshness when their sources changed.
• I removed secrets, private repository content, and customer data from fixtures and screenshots.

[codeCraft-Ritik]

Nice work on this! This is a clean and appropriately scoped repository cleanup. Removing the stale Impeccable sidecar without touching runtime code, package inputs, or generated artifacts keeps the change low-risk and easy to review.

The validation is also particularly strong for such a small change. Verifying all 744 tests, git diff --check, and the byte-identical release archive gives good confidence that this cleanup has no unintended impact. Great job keeping the PR focused and well-documented. 👏

[tt-a1i]

The cleanup is appropriately scoped, and the runtime/package evidence looks good, but one acceptance criterion from #158 is still missing.

The PR deletes .impeccable/design.json without adding a root-level ignore rule. The PR head’s .gitignore does not match .impeccable/, so the generated sidecar can be recommitted the next time the tool recreates it. Please add /.impeccable/ to .gitignore (root-anchored so nested paths are unaffected), then update the branch from current main and let the required checks rerun.

[tt-a1i]

Code Review Summary

Verdict: Changes Requested 🔴 (1 blocking issue)

⚠️ Warning

• .gitignore — Issue chore: remove unused Impeccable project metadata #158 requires root .impeccable/ output to be ignored, but the PR only deletes the currently tracked sidecar. Add /.impeccable/ so regenerated metadata cannot be recommitted accidentally.

✅ Looks Good

• The deleted sidecar is unreferenced by runtime, build, tests, CI, documentation, and packaging.
• The diff is focused and git diff --check passes.
• All nine checks passed on the current PR head.

The branch is behind main; after the fix, update it and rerun the required checks.