Add per-account-type splitEnabled flag from the catalog

When the master marks an account type splitEnabled=false, big days trade
as one unsplit leg (the legacy one-and-done behavior); min-day bumps are
unaffected. Missing field — older master or pre-toggle cached catalog —
defaults to enabled.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

types.ts

@@ -11,6 +11,7 @@ export interface AccountConfig {
     maxLoss: number;          // 0 = no limit; positive = account is "Dead" when loss exceeds this
     maxPositionSize: number;  // 0 = no limit; positive = max contracts per trade
     targetSameEquity: boolean;   // if true, reduce profitTarget by priorProfit after withdrawal
+    splitEnabled: boolean;    // false = big days trade as one unsplit leg instead of random ≥$800 pieces
     withdrawalStages: { profit: number; consistency: number; minTradingDays: number }[];  // per-stage fresh profit + consistency (empty = use base values)
 }