improve: 增强进度反馈，捕获TradingAgents实时输出

- 捕获stdout输出同步到前端日志
- 添加等待提示（3-8分钟）
- 过滤有意义的进度信息

web_app.py

@@ -518,6 +518,9 @@ def task_status(task_id):
 
 def run_analysis(task_id, ticker, date):
     """后台运行TradingAgents分析。"""
+    import sys
+    import io
+    
     try:
         task = tasks[task_id]
         
@@ -534,7 +537,7 @@ def run_analysis(task_id, ticker, date):
         
         log(f'📊 开始分析 {ticker} ({date})')
         log(f'🤖 模型: MiMo-v2.5-pro')
-        log(f'🌐 数据源: SSH中转代理')
+        log(f'🌐 数据源: Alpha Vantage + SSH中转代理')
         
         from tradingagents.graph.trading_graph import TradingAgentsGraph
         from tradingagents.default_config import DEFAULT_CONFIG
@@ -558,11 +561,40 @@ def run_analysis(task_id, ticker, date):
         }
         
         log('🔧 配置完成，启动分析引擎...')
+        log('⏳ 分析通常需要3-8分钟，请耐心等待...')
         
-        ta = TradingAgentsGraph(debug=True, config=config)
+        # 捕获stdout输出以获取实时进度
+        class LogCapture:
+            def __init__(self, task):
+                self.task = task
+                self.buffer = ''
+            def write(self, text):
+                self.buffer += text
+                if '\n' in self.buffer:
+                    lines = self.buffer.split('\n')
+                    self.buffer = lines[-1]
+                    for line in lines[:-1]:
+                        line = line.strip()
+                        if line and len(line) > 5:
+                            # 只保留有意义的输出
+                            if any(k in line for k in ['Tool', 'Message', 'Agent', 'failed', 'error', '✅', '❌', '📊', '📈', '💭', '📰', '🔬', '⚠️']):
+                                self.task['logs'].append(f'📋 {line[:100]}')
+                                if len(self.task['logs']) > 50:
+                                    self.task['logs'] = self.task['logs'][-50:]
+            def flush(self):
+                pass
         
-        log('📈 技术分析中...')
-        state, decision = ta.propagate(ticker, date)
+        # 临时捕获输出
+        old_stdout = sys.stdout
+        sys.stdout = LogCapture(task)
+        
+        try:
+            ta = TradingAgentsGraph(debug=True, config=config)
+            
+            log('📈 技术分析师开始工作...')
+            state, decision = ta.propagate(ticker, date)
+        finally:
+            sys.stdout = old_stdout
         
         log(f'✅ 分析完成: {decision}')