Add native Cursor plugin via canonical harness paths

[harshav167]

Summary

Adds a native Cursor plugin by generating .cursor-plugin/plugin.json and .cursor-plugin/marketplace.json from the build. The manifest points at the canonical harness tree already shipped in this repo (.cursor/skills/, .claude/agents/, .cursor/hooks.json) instead of copying a duplicate plugin-cursor/ payload.

Cursor users can install from the marketplace (source: "./") or symlink the repo locally. The pre-write blocking hook reuses the same .cursor/hooks.json path and script as project-level installs.

Type of change

• Build system / tooling
• Documentation update

Checklist

• Source files updated in source/ (skill/ unchanged; build/transformer/test sources updated)
• bun run build ran successfully
• bun test passes (tests/hook-build.test.mjs, tests/validate-plugin-versions.test.js)
• Tested with at least one provider (Cursor — smoke-tested pre-write hook)
• README / DEVELOP.md updated if needed

Test plan

• bun run build:release
• bun test tests/hook-build.test.mjs
• bun test tests/validate-plugin-versions.test.js
• Install plugin locally (ln -sf "$(pwd)" ~/.cursor/plugins/local/impeccable) and verify skill, agent, and hook under Customize

[greptile-apps]

Greptile Summary

This PR introduces a native Cursor plugin by generating .cursor-plugin/plugin.json and .cursor-plugin/marketplace.json from the build, pointing at the canonical harness paths (.cursor/skills/, .claude/agents/, .cursor/hooks.json) that already exist in the repo rather than duplicating a separate plugin-cursor/ payload.

• Build: build.js is extended to generate the two Cursor manifest files after the Claude Code plugin subtree is written; the Cursor manifest reuses rootManifest fields (version, author, description, homepage) and overrides skills, agents, and hooks to point at canonical harness paths.
• Version drift guard: validate-plugin-versions.js now checks .cursor-plugin/marketplace.json, .cursor-plugin/plugin.json, and .cursor/skills/impeccable/SKILL.md against the root source-of-truth version, with corresponding unit tests.
• Housekeeping: README option numbering updated, .cursor/settings.json added to .gitignore, and hooks.js comment clarified to mention the shared Cursor hooks path.

Confidence Score: 5/5

Safe to merge; the new Cursor plugin manifests are generated from the same root source of truth already used for the Claude Code plugin, and the version-drift guard now covers all three new files.

All new files are generated by the build and cross-checked by the expanded version validator. Tests cover both drift-detection and the happy path. The only lingering concern — a hardcoded command count string in the marketplace metadata.description template — was already raised in a prior review comment and does not affect runtime correctness.

scripts/build.js — the hardcoded '23 commands' in the cursor marketplace metadata.description template is not validated by generateCounts; already flagged in a prior comment.

Important Files Changed

Filename	Overview
scripts/build.js	Generates .cursor-plugin manifests from rootManifest; the metadata.description string hardcodes "23 commands" and is not in filesToCheck, so it will silently drift if the command count changes (already flagged in a prior review comment).
scripts/lib/validate-plugin-versions.js	Correctly adds .cursor-plugin/marketplace.json, .cursor-plugin/plugin.json, and .cursor/skills/impeccable/SKILL.md to the version-drift checks; logic is clean and consistent with existing checks.
tests/validate-plugin-versions.test.js	Adds two well-structured test cases for drifted and matching Cursor plugin files; fixtures cover all three new version-bearing paths.
tests/hook-build.test.mjs	New integration test verifies plugin.json points at canonical harness paths, hooks manifest matches builder output, and all required canonical files exist; correct and thorough.
.cursor-plugin/plugin.json	Generated manifest; skills/agents/hooks fields correctly point at canonical harness paths; version matches root.
.cursor-plugin/marketplace.json	Generated marketplace manifest; source "./" correctly points at repo root; version matches plugin.json.
scripts/lib/transformers/hooks.js	Comment-only update clarifying the shared Cursor hooks path; no logic changes.
README.md	Option numbering updated and Cursor native plugin install instructions added; accurate and complete.
.gitignore	Correctly gitignores .cursor/settings.json (per-developer workspace settings).

_{Reviews (2): Last reviewed commit: "Point Cursor plugin at canonical harness..." | Re-trigger Greptile}