Account change details (#5190)

## Summary
Accounts setting page to change a users password or username
Fix huge bug were users can see admin settings due to hard code
admin=true
## Testing
- not run (not requested)

------
[Codex
Task](https://chatgpt.com/codex/tasks/task_b_6934b8ecdbf08328a0951b46db77dfd2)

frontend/src/core/services/accountService.ts

@@ -56,4 +56,14 @@ export const accountService = {
     formData.append('newPassword', newPassword);
     await apiClient.post('/api/v1/user/change-password-on-login', formData);
   },
+
+  /**
+   * Change username
+   */
+  async changeUsername(newUsername: string, currentPassword: string): Promise<void> {
+    const formData = new FormData();
+    formData.append('currentPasswordChangeUsername', currentPassword);
+    formData.append('newUsername', newUsername);
+    await apiClient.post('/api/v1/user/change-username', formData);
+  },
 };