Vest: no leg opens into a market close, and accounts plan on Vest's day

Market close: a Vest entry now needs its symbol's market to stay open
for RESET_CLEAR_HOLDS holds of the leg (clearsClose), the clearance the
8 PM ET reset already gets: at the target hold, and at the leg's sized
hold when a leverage cap stretches it. That covers the weekly close and
the daily maintenance hour as Vest's market-hours periods list them.
Before a closure that runs past an 8 PM ET reset (the weekend, a
holiday: longClosure), the bot's own legs still open in the last 5
minutes are closed at market, loudly; a position the bot didn't open is
named in the log and left alone.

Vest's day: Vest accounts are planned, and their legs and entries
counted, on Vest's day (20:00 ET) instead of the Central date
(tradeDateFor, PlatformClient.tradeDate). Between 5 PM CT and the reset
the Central date counted the open Vest day as a prior day and as today's
realized P&L both ($3,000 to go, $800 made: $2,050 left, not $1,900) and
started the leg count over. Other platforms keep the Central date.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/platform-client.ts

@@ -145,6 +145,11 @@ export interface PlatformClient {
      * before the platform's daily reset (resetClearStop).
      */
     dayGainForRoom?(accountId: number, o: { leg: number; limit: number }): number;
+    /** The trade date at `now` (epoch ms) that this platform's daily rows and
+     *  realized P&L follow, where its day turns at another hour than the
+     *  5 PM CT roll (Vest: 20:00 ET). The engine plans the accounts and
+     *  counts their legs by it (tradeDateFor); absent = currentTradeDateCT. */
+    tradeDate?(now: number): string;
     /** Payouts made since the firm's last daily reset — what picks the stage
      *  of an account type whose stages reset each day. */
     sameDayClaims?(accountId: number): number;