fix: dashboard metrics — real drawdown baseline, realized/unrealized split, risk radar fields

- Max drawdown was double-broken: the backend built the equity curve on a
  hardcoded $10k baseline (understating a small account's drawdown ~20x) and
  the frontend multiplied the already-percent value by 100 again (0.87% shown
  as -86.9%). The curve now starts from the trader's real initial balance
  (10k fallback when unknown) and the UI renders the percent once; the demo
  engine and type docs are aligned to percent semantics.
- Header now separates equity-based 'Total P/L (incl. unrealized)' from
  'Realized P/L (closed trades)' so it no longer contradicts profit factor /
  win rate, and the stats strip shows the fee-drag chain
  (gross - fees = net) plus a per-trade-labelled sharpe.
- Risk radar read a non-existent account field (total_unrealized_profit) so
  unrealized PnL always showed $0; small PnLs also render with cents now.
- Nav 'Connect Hyperliquid' turns into a green connected chip when the server
  already holds a fully-authorized exchange, instead of nagging forever from
  a browser without the localStorage flow state.

api/handler_order.go

@@ -237,7 +237,7 @@ func (s *Server) handlePositionHistory(c *gin.Context) {
 	}
 
 	// Get statistics
-	stats, _ := store.Position().GetFullStatsByTraderFilters(traderIDs, traderIDPatterns)
+	stats, _ := store.Position().GetFullStatsByTraderFilters(traderIDs, traderIDPatterns, trader.GetInitialBalance())
 
 	// Get symbol stats
 	symbolStats, _ := store.Position().GetSymbolStatsByTraderFilters(traderIDs, traderIDPatterns, 10)