Add admin password reset option for users (#5180)

## Summary
- add backend support for admins to reset user passwords and optionally
email notifications when SMTP is enabled
- surface mail capability in admin settings data for the UI
- add a shared change-password modal hooked into People and Team user
actions with random password generation and email options

## Testing
- not run (not requested)


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[Codex
Task](https://chatgpt.com/codex/tasks/task_b_6934b978fe3c83289b5b95dec79b3d38)

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Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

frontend/src/proprietary/services/userManagementService.ts

@@ -37,6 +37,7 @@ export interface AdminSettingsData {
   grandfatheredUserCount: number;
   licenseMaxUsers: number;
   premiumEnabled: boolean;
+  mailEnabled: boolean;
 }
 
 export interface CreateUserRequest {
@@ -97,6 +98,15 @@ export interface InviteToken {
   expiresAt: string;
 }
 
+export interface ChangeUserPasswordRequest {
+  username: string;
+  newPassword?: string;
+  generateRandom?: boolean;
+  sendEmail?: boolean;
+  includePassword?: boolean;
+  forcePasswordChange?: boolean;
+}
+
 /**
  * User Management Service
  * Provides functions to interact with user management backend APIs
@@ -254,4 +264,31 @@ export const userManagementService = {
     const response = await apiClient.post<{ deletedCount: number }>('/api/v1/invite/cleanup');
     return response.data;
   },
+
+  /**
+   * Change another user's password (admin only)
+   */
+  async changeUserPassword(data: ChangeUserPasswordRequest): Promise<void> {
+    const formData = new FormData();
+    formData.append('username', data.username);
+    if (data.newPassword) {
+      formData.append('newPassword', data.newPassword);
+    }
+    if (data.generateRandom !== undefined) {
+      formData.append('generateRandom', data.generateRandom.toString());
+    }
+    if (data.sendEmail !== undefined) {
+      formData.append('sendEmail', data.sendEmail.toString());
+    }
+    if (data.includePassword !== undefined) {
+      formData.append('includePassword', data.includePassword.toString());
+    }
+    if (data.forcePasswordChange !== undefined) {
+      formData.append('forcePasswordChange', data.forcePasswordChange.toString());
+    }
+
+    await apiClient.post('/api/v1/user/admin/changePasswordForUser', formData, {
+      suppressErrorToast: true, // Component will handle error display
+    } as any);
+  },
 };