Upgrade MCP server SDK to 2.0 - #2

Summary

• replace the v1 umbrella SDK with @modelcontextprotocol/server 2.0 and use the official createMcpHandler HTTP entry point
• move bearer validation onto SDK requireBearerAuth while preserving Supabase token scoping and RFC 9728 protected-resource metadata
• migrate all tool inputs to complete Standard Schema objects and remove redundant handler-side validation
• add the v2 client as a dev-only E2E harness and verify authenticated protocol negotiation, discovery, and team_list
• declare the Node 20.9 minimum shared by Next.js and MCP v2

Compatibility notes

• modern 2026-07-28 traffic uses JSON response mode
• 2025-era traffic remains available through the SDK stateless fallback and is covered by the existing server suite
• CORS now permits the modern MCP protocol headers

Verification

• npm run typecheck
• npm test — 92 files, 411 tests
• npm run lint
• npm run build
• npm run test:e2e — 15 tests

References

• MCP TypeScript SDK v2 migration guide
• HTTP serving
• Authorization
• 2026-07-28 support