feat: migrate timestamps to int64 and security improvements

- Convert all time.Time fields to int64 Unix milliseconds (UTC)
- Add PostgreSQL migration to convert timestamp columns to bigint
- Reduce Binance sync window from 7 days to 24 hours
- Fix dashboard trader name visibility (add nofx-text-main color)
- Add position value column to history table
- Remove hardcoded API keys from test files

web/src/i18n/translations.ts

@@ -1134,6 +1134,7 @@ export const translations = {
       entry: 'Entry',
       exit: 'Exit',
       qty: 'Qty',
+      value: 'Value',
       lev: 'Lev',
       pnl: 'P&L',
       duration: 'Duration',
@@ -2280,6 +2281,7 @@ export const translations = {
       entry: '开仓价',
       exit: '平仓价',
       qty: '数量',
+      value: '仓位价值',
       lev: '杠杆',
       pnl: '盈亏',
       duration: '持仓时长',