fix: update user fields to match schema

- Replace firstName/lastName with name field in users API route
- Update user formatting in UsersTab component
- Add email fallback when name is not available

src/app/api/studies/[id]/users/route.ts

@@ -0,0 +1,73 @@
+import { eq, and } from "drizzle-orm";
+import { db } from "~/db";
+import { userRolesTable, usersTable, rolesTable } from "~/db/schema";
+import { PERMISSIONS, checkPermissions } from "~/lib/permissions-server";
+import { ApiError, createApiResponse } from "~/lib/api-utils";
+
+export async function GET(
+  request: Request,
+  context: { params: { id: string } }
+) {
+  try {
+    const { id } = await context.params;
+    const studyId = parseInt(id);
+
+    if (isNaN(studyId)) {
+      return ApiError.BadRequest("Invalid study ID");
+    }
+
+    const permissionCheck = await checkPermissions({
+      studyId,
+      permission: PERMISSIONS.VIEW_STUDY
+    });
+
+    if (permissionCheck.error) {
+      return permissionCheck.error;
+    }
+
+    // Get all users in the study with their roles
+    const studyUsers = await db
+      .select({
+        id: usersTable.id,
+        email: usersTable.email,
+        name: usersTable.name,
+        roleId: rolesTable.id,
+        roleName: rolesTable.name,
+      })
+      .from(userRolesTable)
+      .innerJoin(usersTable, eq(usersTable.id, userRolesTable.userId))
+      .innerJoin(rolesTable, eq(rolesTable.id, userRolesTable.roleId))
+      .where(eq(userRolesTable.studyId, studyId));
+
+    // Group roles by user
+    const users = studyUsers.reduce((acc, curr) => {
+      const existingUser = acc.find(u => u.id === curr.id);
+      if (!existingUser) {
+        acc.push({
+          id: curr.id,
+          email: curr.email,
+          name: curr.name,
+          roles: [{
+            id: curr.roleId,
+            name: curr.roleName,
+          }]
+        });
+      } else if (curr.roleName && !existingUser.roles.some(r => r.id === curr.roleId)) {
+        existingUser.roles.push({
+          id: curr.roleId,
+          name: curr.roleName,
+        });
+      }
+      return acc;
+    }, [] as Array<{
+      id: string;
+      email: string;
+      name: string | null;
+      roles: Array<{ id: number; name: string }>;
+    }>);
+
+    return createApiResponse(users);
+  } catch (error) {
+    return ApiError.ServerError(error);
+  }
+}