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/components/PositionHistory.tsx

@@ -303,6 +303,11 @@ function PositionRow({ position }: { position: HistoricalPosition }) {
         {displayQty.toFixed(4)}
       </td>
 
+      {/* Position Value (Entry Price * Quantity) */}
+      <td className="py-3 px-4 text-right font-mono" style={{ color: '#EAECEF' }}>
+        {formatNumber(entryPrice * displayQty)}
+      </td>
+
       {/* P&L */}
       <td className="py-3 px-4 text-right">
         <div className="font-mono font-semibold" style={{ color: pnlColor }}>
@@ -764,6 +769,12 @@ export function PositionHistory({ traderId }: PositionHistoryProps) {
                 >
                   {t('positionHistory.qty', language)}
                 </th>
+                <th
+                  className="py-3 px-4 text-right text-xs font-semibold uppercase tracking-wider"
+                  style={{ color: '#848E9C' }}
+                >
+                  {t('positionHistory.value', language)}
+                </th>
                 <th
                   className="py-3 px-4 text-right text-xs font-semibold uppercase tracking-wider"
                   style={{ color: '#848E9C' }}

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',

web/src/pages/TraderDashboardPage.tsx

@@ -361,7 +361,7 @@ export function TraderDashboardPage({
                                 <div className="absolute -bottom-1 -right-1 w-4 h-4 bg-nofx-green rounded-full border-2 border-[#0B0E11] shadow-[0_0_8px_rgba(14,203,129,0.8)] animate-pulse" />
                             </div>
                             <div className="flex flex-col">
-                                <span className="text-3xl tracking-tight bg-clip-text text-transparent bg-gradient-to-r from-nofx-text-main to-nofx-text-muted">
+                                <span className="text-3xl tracking-tight text-nofx-text font-semibold">
                                     {selectedTrader.trader_name}
                                 </span>
                                 <span className="text-xs font-mono text-nofx-text-muted opacity-60 flex items-center gap-2">