fix: harden auth and investment synchronization

Resolve A01-A10 and C01-C07 from the backend audit.
Preserve auth failures, forced candle reconciliation and forecast freshness.
Validate MOEX responses and nested HTTP errors; remove unused legacy paths.

Verified: 209 unit tests, 262 SQLite e2e tests on Linux, OpenAPI and durability.
Record the remaining macOS native SQLite abort in the audit.

src/modules/investments/operations/infrastructure/brokerage-operation.mapper.ts

@@ -10,6 +10,8 @@ import {
   OperationCategory,
 } from '../presentation/brokerage-operation.dto';
 
+const NANOSECONDS_PER_MILLISECOND = 1_000_000;
+
 const types: Record<string, OperationCategory> = {
   OPERATION_TYPE_BUY: 'trade',
   OPERATION_TYPE_BUY_CARD: 'trade',
@@ -42,10 +44,11 @@ export function operationCategory(type: string | undefined): OperationCategory {
 
 export function mapBrokerageOperation(
   operation: TbankOperationItem,
+  occurredAt = operationTimestamp(operation.date),
 ): BrokerageOperationDto {
   return {
     id: operation.id ?? operation.cursor ?? '',
-    occurredAt: timestamp(operation.date),
+    occurredAt: occurredAt.toISOString(),
     type: operation.type ?? 'OPERATION_TYPE_UNSPECIFIED',
     category: operationCategory(operation.type),
     description: operation.description?.trim() || operation.name?.trim() || '',
@@ -82,10 +85,11 @@ function money(value: TbankMoney | undefined) {
     : null;
 }
 
-function timestamp(
+export function operationTimestamp(
   value: { seconds?: string | number; nanos?: number } | undefined,
 ) {
   return new Date(
-    Number(value?.seconds ?? 0) * MILLISECONDS_PER_SECOND,
-  ).toISOString();
+    Number(value?.seconds ?? 0) * MILLISECONDS_PER_SECOND +
+      Math.floor((value?.nanos ?? 0) / NANOSECONDS_PER_MILLISECOND),
+  );
 }