plugin-mcp: find tool is missing populate, joins, trash, and pagination args

[jhb-dev]

The MCP plugin's find tool is missing several useful arguments supported by payload.find / payload.findByID:

• populate — controls which fields to include from populated documents, useful for reducing response size
• joins — controls join field queries; can pass false to disable all join fields
• trash — includes soft-deleted documents in query results
• pagination — set to false to skip the count query overhead

These should be added as optional parameters to the find tool's schema and passed through to the underlying calls.

File: packages/plugin-mcp/src/mcp/tools/resource/find.ts

[naaa760]

Hello! @jhb-dev
please check out this PR!