feat: implement dual stop system and database tracking

- Add PostgreSQL database with Prisma ORM
  - Trade model: tracks entry/exit, P&L, order signatures, config snapshots
  - PriceUpdate model: tracks price movements for drawdown analysis
  - SystemEvent model: logs errors and system events
  - DailyStats model: aggregated performance metrics

- Implement dual stop loss system (enabled by default)
  - Soft stop (TRIGGER_LIMIT) at -1.5% to avoid wicks
  - Hard stop (TRIGGER_MARKET) at -2.5% to guarantee exit
  - Configurable via USE_DUAL_STOPS, SOFT_STOP_PERCENT, HARD_STOP_PERCENT
  - Backward compatible with single stop modes

- Add database service layer (lib/database/trades.ts)
  - createTrade(): save new trades with all details
  - updateTradeExit(): close trades with P&L calculations
  - addPriceUpdate(): track price movements during trade
  - getTradeStats(): calculate win rate, profit factor, avg win/loss
  - logSystemEvent(): log errors and system events

- Update execute endpoint to use dual stops and save to database
  - Calculate dual stop prices when enabled
  - Pass dual stop parameters to placeExitOrders
  - Save complete trade record to database after execution

- Add test trade button to settings page
  - New /api/trading/test endpoint for executing test trades
  - Displays detailed results including dual stop prices
  - Confirmation dialog before execution
  - Shows entry price, position size, stops, and TX signature

- Generate Prisma client in Docker build
- Update DATABASE_URL for container networking

Dockerfile

@@ -35,6 +35,9 @@ COPY --from=deps /app/node_modules ./node_modules
 # Copy source code
 COPY . .
 
+# Generate Prisma client before building
+RUN npx prisma generate
+
 # Build Next.js application
 ENV NEXT_TELEMETRY_DISABLED 1
 ENV NODE_ENV production