fix(claude): properly structure claude plugin (#14432)

Fix for #14403 . The marketplace could be added, plugin installed.
However, the command was not available after installation.

Author: denolfe

.claude-plugin/marketplace.json

@@ -1,13 +1,21 @@
 {
-  "name": "payload",
+  "name": "payload-marketplace",
+  "version": "0.0.1",
+  "description": "Development marketplace for Payload",
   "owner": {
     "name": "Payload",
     "email": "info@payloadcms.com"
   },
   "plugins": [
     {
       "name": "payload",
-      "source": "./"
+      "description": "Payload Development plugin - covers collections, fields, hooks, access control, plugins, and database adapters.",
+      "version": "0.0.1",
+      "source": "./tools/claude-plugin",
+      "author": {
+        "name": "Payload",
+        "email": "info@payloadcms.com"
+      }
     }
   ]
 }

.claude-plugin/plugin.json renamed to tools/claude-plugin/.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "payload",
   "version": "0.0.1",
-  "description": "Payload CMS 3.x development skill with TypeScript patterns, field configs, hooks, access control, and API examples",
+  "description": "Payload Development plugin - covers collections, fields, hooks, access control, plugins, and database adapters.",
   "author": {
     "name": "Payload",
     "email": "info@payloadcms.com",
@@ -10,6 +10,5 @@
   "homepage": "https://github.com/payloadcms/payload",
   "repository": "https://github.com/payloadcms/payload",
   "license": "MIT",
-  "keywords": ["payload", "cms", "payload-cms", "nextjs", "typescript", "headless-cms"],
-  "commands": "./commands"
+  "keywords": ["payload", "cms", "payload-cms", "nextjs", "typescript", "headless-cms"]
 }