perf: optimize system concurrency, I/O stability and fix WebSocket disconnects

backend/services/gateway_cycle_support.py

@@ -253,7 +253,8 @@ async def finalize_cycle(gateway: Any, date: str) -> None:
 
 async def get_market_caps(gateway: Any, tickers: list[str], date: str) -> dict[str, float]:
     market_caps: dict[str, float] = {}
-    for ticker in tickers:
+
+    async def _get_one(ticker: str):
         try:
             market_cap = None
             response = await gateway._call_trading_service(
@@ -263,12 +264,21 @@ async def get_market_caps(gateway: Any, tickers: list[str], date: str) -> dict[s
             if response is not None:
                 market_cap = response.get("market_cap")
             if market_cap is None:
-                payload = trading_domain.get_market_cap_payload(ticker=ticker, end_date=date)
+                payload = await asyncio.to_thread(
+                    trading_domain.get_market_cap_payload,
+                    ticker=ticker,
+                    end_date=date,
+                )
                 market_cap = payload.get("market_cap")
-            market_caps[ticker] = market_cap if market_cap else 1e9
+            return ticker, (market_cap if market_cap else 1e9)
         except Exception as exc:
             logger.warning("Failed to get market cap for %s, using default 1e9: %s", ticker, exc)
-            market_caps[ticker] = 1e9
+            return ticker, 1e9
+
+    tasks = [_get_one(ticker) for ticker in tickers]
+    results = await asyncio.gather(*tasks)
+    for ticker, mc in results:
+        market_caps[ticker] = mc
     return market_caps