fix: 优化Yahoo Finance跳过策略 + Polymarket超时

- yf_retry: 直接抛出YFRateLimitError，跳过本地重试
- Polymarket: 直连超时从30s降到5s，快速fallback到SSH
- 基础数据(yf_retry调用)将优雅降级，不阻塞分析流程

tradingagents/dataflows/polymarket.py

@@ -24,7 +24,10 @@ logger = logging.getLogger(__name__)
 GAMMA_BASE = "https://gamma-api.polymarket.com"
 
 # Network timeout (seconds), consistent with the other vendors.
-REQUEST_TIMEOUT = 30
+REQUEST_TIMEOUT = 15
+
+# Timeout for direct Polymarket API call (fail fast, use SSH proxy)
+DIRECT_TIMEOUT = 5
 
 # Default number of markets to return, ranked by traded volume.
 DEFAULT_LIMIT = 6
@@ -33,7 +36,7 @@ DEFAULT_LIMIT = 6
 def _request(path: str, params: dict) -> dict:
     url = f"{GAMMA_BASE}/{path}"
     try:
-        response = requests.get(url, params=params, timeout=REQUEST_TIMEOUT)
+        response = requests.get(url, params=params, timeout=DIRECT_TIMEOUT)
         response.raise_for_status()
         return response.json()
     except requests.RequestException: