Adds marketplace scaffolding (.claude-plugin/marketplace.json,
.github/plugin/marketplace.json) and a hello-world proof-of-concept
plugin to validate the format before migrating real skills.
Also fixes inventory.sh to include .agents/ in the hidden-dir exception
list so audits correctly surface the 16 existing skills.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds a new skill for creating, managing, and adopting plugins across
Claude Code and GitHub Copilot CLI marketplaces. Includes three Bash
scripts (inventory, gen_manifests, validate), three reference docs
(cross-compat, claude-code, copilot-cli), a test harness with 18
passing tests, and an eval.yaml. Also adds the `marketplace` category
to CATEGORIES.md and commits the plugin marketplace architecture
research doc that informed the skill design.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
