[Hardening] F-09: No Email Alerts for Security-Relevant Events.

### The required feature described as a wish

**Description:** CloudStack does not send email notifications to users or administrators when security-relevant events occur on their accounts. Specifically, no alerts are generated for password changes, creation of API keys, failed login attempts, or exposure of data containing secrets, such as `kubeconfig`.

**Affected Components:** Management

**Impact:** Since users have no out-of-band visibility into actions taken on their accounts, an attacker may go undetected indefinitely, establish persistence by creating API keys, try to guess users' passwords, attempt to access users' accounts from an unauthorized source (see F-12), or silently lock the user out by resetting their password. This significantly increases the window of exposure following a credential compromise.

**Steps to Reproduce:**
- Log in to the CloudStack Management UI as any user.
- Change your own password.
- Generate API keys.
- Reveal Kubernetes configuration.
- Attempt to log in with an incorrect password.
- Attempt to log in from an unauthorized source.
- Check for an email notification confirming that any of the above actions occurred.

**Recommended Remediation:** Implement email notifications for security-sensitive account events, including but not limited to the ones listed above. Each notification should include the timestamp, source IP address, and nature of the action performed. All triggering events should additionally be recorded as audit log entries to support forensic investigation and compliance reporting.

ソースファイルやテストは指定されていません。まず、パスワード変更、API-key の作成、失敗したログインまたは認証されていないログイン、Kubernetes 設定の露出に関する Management UI のフローから始め、続いてそれらの audit-log の処理と通知経路を追跡してください。完了の条件は、一覧にある各セキュリティイベントが必要な監査データを記録し、timestamp、source IP、action を含むメールを送信することです。

索引モデルが issue の本文から書いたものです。