refactor(chat): remove weekly limit flow

src/app/chat/components/chat-quota-exhausted-banner.tsx

@@ -1,14 +1,14 @@
 "use client";
 /**
- * ChatQuotaExhaustedBanner 游客配额耗尽横幅
+ * ChatQuotaExhaustedBanner 发送受限横幅
  *
  * 何时显示：
- *   - 后端返回 lockDetail.reason="weekly_limit" 且 showUpgrade=true
+ *   - 后端返回 cannotSendReason="insufficient_credits"
  *
  * 视觉规格（与设计稿对齐）：
  *   - 粉→品红渐变背景（与 splash 渐变一致）
- *   - 大字号粉色/白色提示文案（"The limit for free chat times has been reached today"）
- *   - 粉→品红渐变 pill 按钮"Unlock your membership to continue" → 跳 /subscription
+ *   - 大字号粉色/白色提示文案
+ *   - 粉→品红渐变 pill 按钮 → 跳 /subscription
  *
  * 业务关系：
  *   - 与 `src/app/sidebar/components/vip-benefits-card.tsx` 的 "Activate VIP Membership" 行为一致
@@ -36,8 +36,8 @@ export interface ChatQuotaExhaustedBannerProps {
 }
 
 export function ChatQuotaExhaustedBanner({
-  title = "The limit for free chat times\nhas been reached today",
-  ctaLabel = "Unlock your membership to continue",
+  title = "Insufficient credits\nTop up to continue chatting",
+  ctaLabel = "Top up credits to continue",
   onUnlock,
 }: ChatQuotaExhaustedBannerProps) {
   const router = useRouter();