Tradeify247: each person sizes a little apart from everyone else

Every machine sized a like account in a like state to the same position as
every other person's, so two people's positions could match to the unit.
Each person now draws a size factor in [0.85, 1.15] per trade date, seeded
by the master's uuid for them; all of one person's accounts share it.

The factor moves the hold a DXtrade leg is sized for (hold / factor², since
size goes as 1/√hold), so the instrument pick, the dashboard's next leg and
the Firms page's reach test all see the hold the size was made for.

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

lib/dxtrade-class.ts

@@ -32,7 +32,8 @@
  */
 
 import axios from './http-client';
-import { currentTradeDateCT, FIRM_RESET_UTC_HOUR, DEFAULT_TARGET_HOLD_HOURS, rankForTarget } from './trading-logic';
+import { currentTradeDateCT, FIRM_RESET_UTC_HOUR, rankForTarget } from './trading-logic';
+import { sizingHoldHours } from './person-size';
 import {
     saveDailyPnL, loadDailyPnL, loadAccountMeta, saveAccountMeta, loadFundTransactions, saveFundTransactions,
     saveEndedCycleStart,
@@ -1222,7 +1223,7 @@ export class DXTradeClient implements PlatformClient {
         const ref = this.referenceAccount();
         if (!ref) return null;
         const firm = getCachedFirm(this.cfg.firmId);
-        const targetHold = firm?.targetHoldHours || DEFAULT_TARGET_HOLD_HOURS;
+        const targetHold = sizingHoldHours(firm);
         const symbols = [...new Set(candidates.map((c) => c.symbol))];
         const [insts, dets, quotes, vols] = await Promise.all([
             this.instruments(symbols),