fix(plugin-mcp): adds collection and strategy to user (#14981)

Fixes: #14923

Correctly adds `collectionSlug` and `_strategy` to the `user` when using
MCP operations.

Author: kendelljoseph

packages/plugin-mcp/src/endpoints/mcp.ts

@@ -1,5 +1,5 @@
 import crypto from 'crypto'
-import { type PayloadHandler, UnauthorizedError, type Where } from 'payload'
+import { type PayloadHandler, type TypedUser, UnauthorizedError, type Where } from 'payload'
 
 import type { MCPAccessSettings, PluginMCPServerConfig } from '../types.js'
 
@@ -57,6 +57,14 @@ export const initializeMCPHandler = (pluginOptions: PluginMCPServerConfig) => {
         payload.logger.info('[payload-mcp] API Key is valid')
       }
 
+      const user = docs[0]?.user as TypedUser
+      const customUserCollection =
+        typeof pluginOptions.userCollection === 'string'
+          ? pluginOptions.userCollection
+          : pluginOptions.userCollection?.slug
+      user.collection = customUserCollection ?? 'users'
+      user._strategy = 'mcp-api-key' as const
+
       return docs[0] as unknown as MCPAccessSettings
     }