Update webhook closed PR message link to clau.de

Replace the Google Forms link with the new plugin directory
submission link (https://clau.de/plugin-directory-submission).

https://claude.ai/code/session_01NxRDJKDvFR2d4wC4ppDEDT

.claude-plugin/marketplace.json

@@ -684,17 +684,6 @@
         "url": "https://github.com/semgrep/mcp-marketplace.git"
       },
       "homepage": "https://github.com/semgrep/mcp-marketplace.git"
-    },
-    {
-      "name": "planetscale",
-      "description": "An authenticated hosted MCP server that accesses your PlanetScale organizations, databases, branches, schema, and Insights data. Query against your data, surface slow queries, and get organizational and account information.",
-      "category": "database",
-      "source": {
-        "source": "url",
-        "url": "https://github.com/planetscale/claude-plugin.git",
-        "sha": "f1066cac5bb956bbbb05918f5b07fe0e873d44ea"
-      },
-      "homepage": "https://planetscale.com/"
     }
   ]
 }