MCP server v2.19.0: MCP-managed schemas and deploy_studio tool

New Features

deploy_studio tool: Deploys a hosted Sanity Studio bound to an MCP-managed schema. Given an appHost, the tool provisions or redeploys a Studio at https://<appHost>.sanity.studio/ that renders the managed schema and is available in Sanity Dashboard.

MCP-managed schemas: Schemas deployed via deploy_schema are now owned and resolved by the MCP server directly, rather than relying on a Studio codebase to publish them. get_schema, list_workspace_schemas, and the document tools read from this managed source first, falling back to Studio-deployed and legacy schemas when no managed schema exists for a workspace.

Fixes

Legacy schema adoption: Better handles invalid legacy schema manifests by returning clear recovery guidance instead of leaking raw validation errors.