fix(server): add missing graphile-utils dependency

The server package imports graphile-utils in PublicKeySignature plugin
but the dependency was not declared in package.json, causing
MODULE_NOT_FOUND errors when running CLI commands that load the server
module (e.g., init command).

Add graphile-utils dependency to ensure proper module resolution.

Author: sdqede

packages/server/package.json

@@ -61,6 +61,7 @@
     "graphile-search-plugin": "^0.1.2",
     "graphile-settings": "^2.5.3",
     "graphile-simple-inflector": "^0.1.1",
+    "graphile-utils": "^4.14.1",
     "pg-cache": "workspace:^",
     "graphql-tag": "2.12.6",
     "graphql-upload": "^13.0.0",