fix(ci): add zod to root devDependencies for MCP test imports

Tests import mcp/src/tools.ts which requires zod, but only mcp/
had it as a dependency. CI runs npm ci at root level only.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: TheBlueHouse75

package-lock.json

@@ -57,6 +57,7 @@
     "tsup": "^8.3.5",
     "tsx": "^4.19.2",
     "typescript": "^5.7.2",
-    "vitest": "^4.0.18"
+    "vitest": "^4.0.18",
+    "zod": "^4.3.6"
   }
 }