chore(deps): update dependency @modelcontextprotocol/sdk to v1.21.1 (#1396)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

packages/ai/package.json

@@ -24,7 +24,7 @@
     "client": "npm run build && node dist/mcp/index.js"
   },
   "devDependencies": {
-    "@modelcontextprotocol/sdk": "1.20.2",
+    "@modelcontextprotocol/sdk": "1.21.1",
     "@rsdoctor/types": "workspace:*",
     "@rsdoctor/utils": "workspace:*",
     "@rstest/core": "0.5.4",