feat(hooks): package design hook in plugin, install to settings.local.json (#243)

* feat(hooks): package design hook in plugin, install to settings.local.json

Three related changes to how the Impeccable design hook is distributed,
plus an unrelated build fix discovered along the way.

Package the hook in the Claude Code plugin
- The marketplace / `/plugin install` path previously shipped the skill and
  agents but no hook, so those users never got the design detector. The build
  now emits `plugin/hooks/hooks.json` (auto-discovered at the plugin root),
  resolving the script via `${CLAUDE_PLUGIN_ROOT}` so it works wherever Claude
  Code unpacks the plugin instead of assuming a `.claude/skills/` layout.

CLI installs the hook into settings.local.json, not shared settings.json
- `npx impeccable skills install/update` now writes the Claude hook to the
  gitignored `.claude/settings.local.json` (a machine-local install side
  effect) rather than the team-shared `settings.json`, which could otherwise
  be committed and break for teammates without the skill installed.
- Graceful handling (leave-it-never-duplicate): if our hook already lives in
  the shared `settings.json` (a legacy install or a deliberate user move), it
  is honored in place and never duplicated into the local override, which
  would otherwise run the detector twice per edit.
- The skill's `/impeccable hooks on|off` toggle is unaffected: it only writes
  `.impeccable/hook.json`, never the settings files.

Fix universal.zip build failure under archiver v8
- `archiver` was bumped to v8 (now ESM, factory function removed) but
  `scripts/lib/zip.js` still used the old `archiver('zip', ...)` API, so every
  build silently failed to produce `dist/universal.zip` (the skill-release
  artifact). Switched to `new ZipArchive({...})`.

Also folds in a pre-existing local rename of the hook status message
("Scanning design" -> "Checking UI changes") and its regenerated provider
output.

Tests: new coverage for the plugin-packaged hook manifest and the
shared-settings honor-in-place path; existing CLI assertions moved to
settings.local.json. Full suite green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(cli): detect hook by marker, not file existence (Bugbot)

hookInstalledForProvider treated any existing settings.local.json (or
hooks.json) as proof the hook was installed. Those files commonly hold
unrelated local settings, so the already-installed `skills install` path
would skip repairing a genuinely missing hook that `update` would add.

Detect the Impeccable marker in the file instead of mere existence. Adds a
test for the exact case: a settings.local.json with only permissions still
triggers hook repair and preserves the unrelated content.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* test(build): fail loud on a broken release zip + cover the zip writer

Close the gap that let the archiver v8 break ship a 0-byte universal.zip
with a green test suite:

- createProviderZip no longer swallows failures. It throws on a missing
  source, an archive with zero entries, or a 0-byte output, and build() now
  exits non-zero on any such rejection. A build that can't produce its release
  artifact fails instead of deploying an empty bundle.
- New tests/zip.test.mjs exercises the real zip writer and round-trips through
  extract-zip (the unpacker the CLI uses): a valid bundle unpacks to the skill
  tree, and the empty/missing-source cases throw. Wired into the core suite so
  it runs in `bun run test`.

Why this matters: the prior CLI e2e tests stub the bundle as a local
directory, so they never built, downloaded, or unzipped a real archive. The
zip writer had no coverage and failed soft, so Dependabot's archiver 7->8
major bump merged green and the deploy shipped an unusable bundle.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(cli): scope hook marker scan to the hooks subtree + prune local dupes (Bugbot)

Two follow-ups from Bugbot:

- fileHasImpeccableHookMarker scanned the whole settings file as raw text, so
  an unrelated string (e.g. a permissions allow entry that mentions the hook
  path) could falsely read as an installed hook and block install/repair or
  the shared-settings skip. Now it parses the JSON and scans only the `hooks`
  subtree.
- When the hook is honored in the shared settings.json, copyProviderHooks
  skipped the local write but left a stale hook in settings.local.json from an
  earlier machine-local install, so Claude Code loaded both and ran the
  detector twice per edit. It now prunes the local copy (preserving unrelated
  local settings, dropping the file if only our scaffolding remained).

Adds tests for both: a permissions string mentioning the hook path still
triggers repair, and a shared hook prunes the stale local duplicate while
keeping unrelated permissions.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -264,7 +264,7 @@ On Claude Code, Codex, and Cursor, `npx impeccable skills install` and `npx impe
 
 Installed hook surfaces:
 
-- Claude Code: `.claude/settings.json` runs `${CLAUDE_PROJECT_DIR}/.claude/skills/impeccable/scripts/hook.mjs`.
+- Claude Code: `.claude/settings.local.json` (gitignored, machine-local) runs `${CLAUDE_PROJECT_DIR}/.claude/skills/impeccable/scripts/hook.mjs`. A hook moved into the shared `settings.json` is honored in place.
 - Cursor: `.cursor/hooks.json` runs `.cursor/skills/impeccable/scripts/hook-before-edit.mjs`.
 - Codex: `.codex/hooks.json` runs `.agents/skills/impeccable/scripts/hook.mjs`.