Futures legs respect a firm's per-instrument contract limit

A firm can cap how many contracts of an instrument its accounts may hold
(the catalog's instrumentLimits, set on the master's Firms page). A leg
trades one contract per $1,000, capped by the account type's max contracts
and that limit. The Auto draw sizes each instrument's hold with the capped
count, so a limit that slows a leg past 12 hours takes it out of the draw.

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

lib/master-protocol.ts

@@ -381,6 +381,10 @@ export interface CatalogFirm {
      *  own symbols for DXtrade (see lib/instruments.ts). Absent from a master
      *  from before the lists — then bannedSymbols and symbolMap apply. */
     instruments?: string[];
+    /** Futures firms: the most contracts the firm allows on an instrument,
+     *  by root, for every account type (absent = no limit beyond the type's
+     *  max contracts). */
+    instrumentLimits?: Record<string, number>;
     /** Older masters' way to exclude roots; newer ones derive it from
      *  `instruments`. */
     bannedSymbols: string[];