fix(desktop): DeerFlow UI — ChatArea refactor + ai-elements + dead CSS cleanup

ChatArea retry button uses setInput instead of direct sendToGateway,
fix bootstrap spinner stuck for non-logged-in users,
remove dead CSS (aurora-title/sidebar-open/quick-action-chips),
add ai components (ReasoningBlock/StreamingText/ChatMode/ModelSelector/TaskProgress),
add ClassroomPlayer + ResizableChatLayout + artifact panel

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

crates/zclaw-saas/src/relay/key_pool.rs

@@ -281,6 +281,39 @@ pub async fn delete_provider_key(
     Ok(())
 }
 
+/// Key 使用窗口统计
+#[derive(Debug, Clone)]
+pub struct KeyUsageStats {
+    pub key_id: String,
+    pub window_minute: String,
+    pub request_count: i32,
+    pub token_count: i64,
+}
+
+/// 查询指定 Key 的最近使用窗口统计
+pub async fn get_key_usage_stats(
+    db: &PgPool,
+    key_id: &str,
+    limit: i64,
+) -> SaasResult<Vec<KeyUsageStats>> {
+    let limit = limit.min(60).max(1);
+    let rows: Vec<(String, String, i32, i64)> = sqlx::query_as(
+        "SELECT key_id, window_minute, request_count, token_count \
+         FROM key_usage_window \
+         WHERE key_id = $1 \
+         ORDER BY window_minute DESC \
+         LIMIT $2"
+    )
+    .bind(key_id)
+    .bind(limit)
+    .fetch_all(db)
+    .await?;
+
+    Ok(rows.into_iter().map(|(key_id, window_minute, request_count, token_count)| {
+        KeyUsageStats { key_id, window_minute, request_count, token_count }
+    }).collect())
+}
+
 /// 解析冷却剩余时间（秒）
 fn parse_cooldown_remaining(cooldown_until: &str, now: &str) -> i64 {
     let cooldown = chrono::DateTime::parse_from_rfc3339(cooldown_until);