Three new tables: community_rules, community_rule_versions, moderation_action_rules. Rules are versioned -- editing a rule creates a new version row so historical warnings reference the original text. API endpoints: - GET /api/communities/:did/rules (public) - POST /api/communities/:did/rules (admin) - PUT /api/communities/:did/rules/:id (admin, creates new version) - DELETE /api/communities/:did/rules/:id (admin, soft-delete) - PUT /api/communities/:did/rules/reorder (admin) - GET /api/communities/:did/rules/:id/versions (admin) Includes 34 unit tests covering validation schemas and route handlers. Closes singi-labs/barazo-workspace#97