docs: add ClawHub publishing constraints to CLAUDE.md, agents/CLAUDE.md, GEMINI.md

- cs- prefix for slug conflicts only (ClawHub registry, not repo)
- No paid/commercial service dependencies
- Rate limit: 5 new skills/hour
- plugin.json schema enforcement
- Version must match repo release

GEMINI.md

@@ -22,6 +22,14 @@ Skills are organized into domain folders. Each skill is a directory containing a
 | **Business & Growth** | `business-growth/` |
 | **Finance** | `finance/` |
 
+### ClawHub Publishing Constraints
+
+When skills are published to **ClawHub** (clawhub.com):
+- **cs- prefix for slug conflicts only** — applies only on the ClawHub registry when another publisher already owns the slug. Repo folder names and local skill names are never renamed.
+- **No paid/commercial service dependencies** — skills must not require paid third-party API keys or commercial services unless provided by the project itself.
+- **plugin.json** — ONLY fields: `name`, `description`, `version`, `author`, `homepage`, `repository`, `license`, `skills: "./"`.
+- **Rate limit:** 5 new skills/hour on ClawHub. Use drip publishing for bulk operations.
+
 ### Activating a Skill
 
 To activate a skill, use the folder name. For example: