Tool annotations for functions and external MCP servers

This release adds tool annotation support to the Gram functions framework and persists annotations from external MCP servers to the database.

Features

• Tool annotations in functions framework #1571  - Added ToolAnnotations type allowing function authors to specify annotations via Gram.tool({ annotations: { ... } }). (Author: @simplesagar )
• Persist external MCP tool annotations #1596  - Annotations from external MCP servers in the Catalog are now persisted to the database. (Author: @simplesagar )