Trade only on loaded history; catch early TopstepX fills; fix SI/M2K point values

- Both clients track which accounts this process has loaded history for
  (historyReady). An account restarted, rebuilt, wiped or newly listed is
  ineligible until its fetch lands, instead of trading as a fresh stage-1
  first day; a failed fetch with no cache no longer reads as empty history.
  Waiting accounts get a targeted fetch on the next sync.
- Tradovate holds an account whose start-of-day balance moves without a fill
  (a payout between hourly Cash History runs) until a Cash History books it,
  so a payout-pending account isn't re-traded on its ended cycle.
- Wipe routes forget history through the client and count accounts whose
  history didn't come back as failures.
- TopstepX sendOrder picks up a fill that arrived before the place response,
  and its REST backstop uses the documented Trade/search and Order/search.
- POINT_VALUES: SI 5000 (was 50), M2K 5 (was 10).

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

lib/platform-client.ts

@@ -51,6 +51,18 @@ export interface PlatformClient {
     products: { id: number; name: string }[];
 
     fetchDaysTraded(onlyAccountIds?: number[]): Promise<{ failedAccounts: number }>;
+    /**
+     * Whether the account's history can be planned on. False until this
+     * client has loaded it (right after a restart, a client rebuild, a wipe,
+     * or for an account that just appeared), and on Tradovate while a balance
+     * change the history can't explain — a payout between reports — waits
+     * for a Cash History. The missing rows and withdrawals would otherwise
+     * read as a fresh stage-1 cycle, so such an account must not trade.
+     */
+    historyReady(accountId: number): boolean;
+    /** Drop the account's history from memory (the wipe routes), so it reads
+     *  unloaded until the next fetch rebuilds it. */
+    forgetHistory(accountId: number, accountName: string): void;
     findFrontMonthContract(productName: string): Promise<PlatformContract | null>;
     fetchInstrumentFees(symbols: string[]): Promise<{ [symbol: string]: number }>;