Add user utility functions and tests for OIDC user filtering

app/utils/user.ts

@@ -0,0 +1,11 @@
+import type { User } from "~/types/User";
+
+// Filter users with valid IDs (OIDC users may not have a name)
+export function filterUsersWithValidIds(users: User[]): User[] {
+  return users.filter((user) => user.id?.length > 0);
+}
+
+// Get display name with fallback: name -> displayName -> email -> id
+export function getUserDisplayName(user: User): string {
+  return user.name || user.displayName || user.email || user.id;
+}