feat: Add signalSource field to identify manual vs TradingView trades

- Set signalSource='manual' for Telegram trades, 'tradingview' for TradingView
- Updated analytics queries to exclude manual trades from indicator analysis
- getTradingStats() filters manual trades (TradingView performance only)
- Version comparison endpoint filters manual trades
- Created comprehensive filtering guide: docs/MANUAL_TRADE_FILTERING.md
- Ensures clean data for indicator optimization without contamination

lib/database/views.ts

@@ -143,6 +143,10 @@ export async function getTradingStats(days: number = 30) {
       createdAt: { gte: since },
       status: 'closed',
       isTestTrade: false, // Real trades only
+      OR: [
+        { signalSource: null }, // Old trades without signalSource
+        { signalSource: { not: 'manual' } }, // Exclude manual Telegram trades
+      ],
     },
   })