docs: wire AppKit plugin CLI into create/audit/review Claude commands

[MarioCadenas]

Summary

The /create-core-plugin, /audit-core-plugin, and /review-core-plugin Claude commands previously left the appkit plugin CLI as an interactive footnote. The result was that agents either hung on stdin, hand-edited manifest.json, or skipped the schema/sync checks the CLI provides.

These changes wire the full appkit plugin surface into the three commands and route every CLI result to the matching best-practices category:

• create-core-plugin.md
  • Section 2 split into 2a (non-interactive, default) with the full --placement / --path / --name / --display-name / --description / --resources(-json) / --force invocation, and 2b (interactive fallback) scoped to the beta stability case (the CLI doesn't accept it as a flag).
  • Section 4e gained a tip box that points at --resources-json at scaffold time and appkit plugin add-resource (with --dry-run, --no-required, --fields-json) for resources discovered later.
  • Section 7 now starts with appkit plugin validate, prefers pnpm run sync:template inside the monorepo (matching what promote itself does), shows --require-plugins for forcing inclusion, and adds appkit plugin list --json as a verification step.
  • New Section 8 documents appkit plugin promote {name} --to ga with --dry-run first, steering away from hand-editing the manifest + import barrels.
• audit-core-plugin.md
  • "Available plugins" hint now points at appkit plugin list --dir … --json (with ls as fallback).
  • New Step 3.5 runs plugin validate, plugin list --json, and plugin sync --json, with explicit category/severity routing for any failure or warning.
  • Step 5 folds those CLI results into the matching categories and adds appkit plugin promote --to ga --dry-run as a stability/import-barrel consistency check for beta plugins.
• review-core-plugin.md
  • New Step 5.5 runs the per-plugin CLI cross-checks for the touched plugin set: plugin validate always, plugin sync --json always (covers the orphaned-resource warning when plugins are removed), plugin promote --to ga --dry-run when the diff touches stability or /beta imports, and plugin add-resource --dry-run when the diff adds resources — each tagged with the category and severity to use in Step 6.
  • Step 6 explicitly tells the reviewer to fold the Step 5.5 results into the textual review.

No code changes; documentation only.

Test plan

• Manually run /create-core-plugin with a plugin name + description and confirm the agent uses the non-interactive appkit plugin create invocation (no stdin hang).
• Manually run /audit-core-plugin <existing-plugin> and confirm the new Step 3.5 CLI checks (validate, list --json, sync --json) are executed and folded into the scorecard.
• Manually run /review-core-plugin against a branch that touches a plugin manifest and confirm the new Step 5.5 cross-checks run and feed Step 6.