Remove redundant create-plugin command in favor of existing skill

The create-plugin-scaffold skill already covers the same workflow
with more detail. Remove the command file and commands reference
from the plugin manifest.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ericzakariasson

create-plugin/.cursor-plugin/plugin.json

@@ -24,6 +24,5 @@
   ],
   "skills": "./skills/",
   "rules": "./rules/",
-  "agents": "./agents/",
-  "commands": "./commands/"
+  "agents": "./agents/"
 }