Covers a few gaps in the existing MCP test suite:
- find_nodes filtering by type (wasn't exercised at all)
- create_shape with an invalid type enum (Zod enforcement)
- create_shape with a missing required param (Zod enforcement)
13 tests using InMemoryTransport from @modelcontextprotocol/sdk:
- Tool registration (all 76 tools listed with descriptions)
- new_document, open_file, save_file lifecycle
- Tool execution through MCP protocol (create, fill, delete, query)
- Error paths: no document loaded, nonexistent node, invalid file path
- Full workflow: new → create → nest → query → delete
Fix @open-pencil/core dep in MCP package: workspace:* for local dev
(pnpm publish resolves this to the actual version at publish time).
