Add README, repo guidelines and a version-bump gate

README.md documents what the marketplace is, the dependency graph, install and scope selection, what each plugin carries, the mechanics (charter via SessionStart hook, path-scoped rules via PreToolUse, namespacing and project precedence), measured context cost, requirements, and how to extend a layer. Distribution instructions use the real anonymous-read HTTPS URL, so teammates need no SSH key or token.

CLAUDE.md carries the rules for changing this repository: the version policy, what breaks silently (agent frontmatter as a block scalar, skill description as an invocation condition, no duplicated text between rules/ and skills/, no pinned package versions), and how to test hooks from stdin.

scripts/check-plugins.py enforces the one mistake a review cannot catch: a plugin whose contents changed without a version bump never reaches the team, because version in plugin.json pins the plugin. It also checks monotonic semver, skill name against directory, dependencies shape, broken markdown and ${CLAUDE_PLUGIN_ROOT} references, and marketplace/directory agreement. .githooks/pre-commit and .gitlab-ci.yml run it locally and in CI — both, because core.hooksPath is per-clone and bypassing hooks is forbidden.

.gitignore blocks secrets from a repository that is public by design.

Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com