feat: add kyberforge plugin and rename plugin-create skill

Scaffolds the kyberforge marketplace management plugin (create-plugin and
marketplace-architect skills will live here). Renames the plugin-create
skill directory to create-plugin to match the canonical kebab-order convention.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/kyberforge/hooks/hooks.json

@@ -0,0 +1,3 @@
+{
+  "hooks": {}
+}