feat: 全面SSH中转代理 + mimo-v2.5-pro支持

- Yahoo Finance: 跳过本地限流，直接走SSH中转
- StockTwits: 直连403时自动fallback到SSH中转
- Reddit: 网络不可达时自动fallback到SSH中转
- Polymarket: 网络不可达时自动fallback到SSH中转
- FRED: 配置API Key (825283926dd016ea66e96cc919e047da)
- .env: 新增FRED_API_KEY和OPENAI_COMPATIBLE_API_KEY
- test_xiaomi.py: 小米mimo-v2.5-pro测试脚本

tradingagents/dataflows/stockstats_utils.py

@@ -321,34 +321,18 @@ def load_ohlcv(symbol: str, curr_date: str) -> pd.DataFrame:
         if use_alpha_vantage:
             downloaded = _load_ohlcv_alpha_vantage(symbol, curr_date)
         else:
-            downloaded = None
+            # Skip local Yahoo Finance, go directly through SSH proxy
+            logger.info(f"Yahoo Finance: fetching {canonical} via SSH proxy...")
             try:
-                raw = yf_retry(lambda: yf.download(
-                    canonical,
-                    start=start_str,
-                    end=end_str,
-                    multi_level_index=False,
-                    progress=False,
-                    auto_adjust=True,
-                ))
-                downloaded = _ensure_date_column(raw.reset_index())
-            except Exception as yf_err:
-                pass  # Will try proxy below
-
-            # If local yfinance failed or returned empty, try SSH proxy
-            if downloaded is None or downloaded.empty or "Close" not in downloaded.columns:
-                if downloaded is None or downloaded.empty:
-                    logger.warning(f"Yahoo Finance local failed, trying SSH proxy...")
-                try:
-                    downloaded = _yf_download_via_proxy(canonical, start_str, end_str)
-                except Exception as proxy_err:
-                    raise NoMarketDataError(
-                        symbol, canonical, f"Yahoo Finance proxy also failed: {proxy_err}"
-                    ) from proxy_err
-                if downloaded.empty:
-                    raise NoMarketDataError(
-                        symbol, canonical, f"Yahoo Finance proxy also returned no data"
-                    )
+                downloaded = _yf_download_via_proxy(canonical, start_str, end_str)
+            except Exception as proxy_err:
+                raise NoMarketDataError(
+                    symbol, canonical, f"Yahoo Finance proxy failed: {proxy_err}"
+                ) from proxy_err
+            if downloaded.empty:
+                raise NoMarketDataError(
+                    symbol, canonical, f"Yahoo Finance proxy returned no data"
+                )
             if downloaded.empty or "Close" not in downloaded.columns:
                 raise NoMarketDataError(
                     symbol, canonical, "Yahoo Finance returned no rows"