Add DeepWiki MCP integration to librarian agent

[amondnet]

Description

Integrate DeepWiki MCP server into the librarian agent to enable documentation lookup capabilities.

Changes

• Add DeepWiki MCP server to .mcp.json (SSE type)
• Update librarian agent to use DeepWiki MCP for documentation lookup
• Add DeepWiki to tool reference, parallel execution requirements, and failure recovery sections

Context

The librarian agent needs access to DeepWiki for enhanced documentation retrieval and knowledge management capabilities.