fix: 管理员重置配额补全 monthly 字段并修复 ristretto 缓存异步问题

- 后端 handler：ResetSubscriptionQuotaRequest 新增 Monthly 字段，
  验证逻辑扩展为 daily/weekly/monthly 至少一项为 true
- 后端 service：AdminResetQuota 新增 resetMonthly 参数，
  调用 ResetMonthlyUsage；重置后追加 subCacheL1.Wait()，
  保证 ristretto Del() 的异步删除立即生效，消除重置后
  /v1/usage 返回旧用量数据的竞态窗口
- 后端测试：更新存量测试用例匹配新签名，补充
  TestAdminResetQuota_ResetMonthlyOnly /
  TestAdminResetQuota_ResetMonthlyUsageError 两个新用例
- 前端 API：resetQuota options 类型新增 monthly: boolean
- 前端视图：confirmResetQuota 改为同时重置 daily/weekly/monthly
- i18n：中英文确认提示文案更新，提及每月配额

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

backend/internal/handler/admin/subscription_handler.go

@@ -218,11 +218,12 @@ func (h *SubscriptionHandler) Extend(c *gin.Context) {
 
 // ResetSubscriptionQuotaRequest represents the reset quota request
 type ResetSubscriptionQuotaRequest struct {
-	Daily  bool `json:"daily"`
-	Weekly bool `json:"weekly"`
+	Daily   bool `json:"daily"`
+	Weekly  bool `json:"weekly"`
+	Monthly bool `json:"monthly"`
 }
 
-// ResetQuota resets daily and/or weekly usage for a subscription.
+// ResetQuota resets daily, weekly, and/or monthly usage for a subscription.
 // POST /api/v1/admin/subscriptions/:id/reset-quota
 func (h *SubscriptionHandler) ResetQuota(c *gin.Context) {
 	subscriptionID, err := strconv.ParseInt(c.Param("id"), 10, 64)
@@ -235,11 +236,11 @@ func (h *SubscriptionHandler) ResetQuota(c *gin.Context) {
 		response.BadRequest(c, "Invalid request: "+err.Error())
 		return
 	}
-	if !req.Daily && !req.Weekly {
-		response.BadRequest(c, "At least one of 'daily' or 'weekly' must be true")
+	if !req.Daily && !req.Weekly && !req.Monthly {
+		response.BadRequest(c, "At least one of 'daily', 'weekly', or 'monthly' must be true")
 		return
 	}
-	sub, err := h.subscriptionService.AdminResetQuota(c.Request.Context(), subscriptionID, req.Daily, req.Weekly)
+	sub, err := h.subscriptionService.AdminResetQuota(c.Request.Context(), subscriptionID, req.Daily, req.Weekly, req.Monthly)
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return