fix(mcp): use schema objects for setRequestHandler instead of string literals

Import ListToolsRequestSchema and CallToolRequestSchema from
@modelcontextprotocol/sdk/types.js and pass them to setRequestHandler
instead of raw 'tools/list' and 'tools/call' strings. Updates mocks
in tests to match. Also includes updated DEPENDENCIES.md and
dogfood report.

Author: github-actions[bot]