Add notification system for Claude payment status changes

Detect refund/suspension status changes and generate notifications
stored in Redis. Bell icon in navbar shows unread count badge,
click to expand dropdown with dismiss per-item or read-all.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mail_api.py

@@ -1166,9 +1166,20 @@ async def _check_claude_payment_for_account(email_addr: str) -> dict:
         else:
             status = 'unknown'
 
+        # 查旧状态，状态变化时生成通知
+        old_info = await db_manager.get_claude_payment_status(email_addr)
+        old_status = old_info.get('status') if old_info else None
+
         # 写入数据库
         await db_manager.set_claude_payment_status(email_addr, status, payment_time, refund_time, suspended_time)
 
+        # 仅状态变化时创建通知（避免重复检测重复通知）
+        if status != old_status:
+            if status == 'refunded':
+                await cache.add_notification(email_addr, 'refund', f'{email_addr} 已退款')
+            elif status == 'suspended':
+                await cache.add_notification(email_addr, 'suspension', f'{email_addr} 已封号')
+
         # 如果是支付状态且标题和备注为空，提取收据信息
         if status == 'paid' and payment_msg:
             current_info = await db_manager.get_claude_payment_status(email_addr)
@@ -1308,6 +1319,26 @@ async def get_claude_payment_status() -> ApiResponse:
     await cache.set(cache.payment_key(), statuses, TTL_PAYMENT)
     return ApiResponse(success=True, data=statuses)
 
+# ============================================================================
+# 通知系统
+# ============================================================================
+
+@app.get("/api/notifications")
+async def get_notifications():
+    """获取未读通知列表"""
+    notifications = await cache.get_notifications()
+    return {"success": True, "data": notifications}
+
+@app.post("/api/notifications/dismiss")
+async def dismiss_notification(request: Request):
+    """标记通知已读：传 {id} 移除单条，传 {all:true} 清除全部"""
+    body = await request.json()
+    if body.get('all'):
+        await cache.dismiss_all_notifications()
+    elif body.get('id'):
+        await cache.dismiss_notification(body['id'])
+    return {"success": True}
+
 # ============================================================================
 # 命令行入口
 # ============================================================================