fix(account): show source metadata on empty account and income (WealthLedger/frontend#55)

Share the brokerage access-loss predicate across client, resource query and account VM.

src/shared/api/problem-details.ts

@@ -41,4 +41,14 @@ function isApiErrorCode(
 	return value === expected;
 }
 
-export { ApiErrorCode, apiErrorCode, isApiErrorCode };
+// Confirmed loss of access to the brokerage data. UNAUTHORIZED is a session
+// failure with its own refresh/sign-out path, so it is deliberately excluded.
+function isBrokerageAccessLoss(code?: string): boolean {
+	return [
+		ApiErrorCode.InvalidTbankToken,
+		ApiErrorCode.NotFound,
+		ApiErrorCode.TbankNotConnected,
+	].some(loss => isApiErrorCode(code, loss));
+}
+
+export { ApiErrorCode, apiErrorCode, isApiErrorCode, isBrokerageAccessLoss };