Unknown entries settle only on a sync started after them; filled-after-all and working orders seen

Sixth review round (8e66631):

- An entry of unknown outcome is judged against a good sync that STARTED
  at least 90s after it was declared unknown (lastSyncStartedAt: TopstepX's
  pass start, Tradovate's request time), not one that merely ended then —
  a sequential pass can read the account before a late fill.
- Once the broker shows its fill (a position, or realized P&L moved), the
  entry becomes an ordinary filled one instead of holding the account for
  the rest of the day.
- It never settles while the broker still shows a working order on the
  account: Tradovate now reads working orders from the sync snapshot, and
  its fill-timeout cancel checks Tradovate's answer instead of assuming it.
- A second wipe (after a restart) keeps the pending wipe's pre-wipe fund
  signature instead of overwriting it.

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

lib/platform-client.ts

@@ -48,6 +48,12 @@ export interface PlatformClient {
     syncComplete: boolean;
     /** Epoch ms of the last sync that came back good (0 = never). */
     lastSyncAt: number;
+    /** When that good sync started reading: everything it reported is at
+     *  least this recent (a sequential pass can read an account long before
+     *  it ends). */
+    lastSyncStartedAt?: number;
+    /** Whether the broker still shows a working order on the account. */
+    hasWorkingOrders?(accountId: number): boolean;
     lastFetchErrors: Record<string, string>;
     lastFetchRaw: Record<string, string>;
     recentEntityEvents: { entityType: string; eventType: string; entity: unknown; ts: number }[];