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-operations.repository.ts

@@ -5,7 +5,6 @@ import {
 } from '@nestjs/common';
 import { createHash, randomUUID } from 'node:crypto';
 import { isDeepStrictEqual } from 'node:util';
-import { MILLISECONDS_PER_SECOND } from '../../../../common/time';
 import { PrismaService } from '../../../../prisma/prisma.service';
 import type { Prisma } from '../../../../../generated/prisma/client';
 import type {
@@ -17,7 +16,10 @@ import {
   dateOnlyBounds,
   moscowDate,
 } from '../../investment-calendar';
-import { operationCategory } from './brokerage-operation.mapper';
+import {
+  operationCategory,
+  operationTimestamp,
+} from './brokerage-operation.mapper';
 import {
   type OperationInterval,
   operationIntervals,
@@ -45,7 +47,6 @@ type PageProgress = {
   pages: number;
 };
 const progressItem = '';
-const NANOSECONDS_PER_MILLISECOND = 1_000_000;
 
 @Injectable()
 export class BrokerageOperationsRepository {
@@ -650,13 +651,11 @@ export class BrokerageOperationsRepository {
       for (const operation of response.items ?? []) {
         if (!operation.id?.trim())
           throw new Error('Missing broker operation identity');
-        const occurredAt = new Date(
-          Number(operation.date?.seconds) * MILLISECONDS_PER_SECOND +
-            Math.floor(
-              (operation.date?.nanos ?? 0) / NANOSECONDS_PER_MILLISECOND,
-            ),
-        );
-        if (!Number.isFinite(occurredAt.valueOf()))
+        const occurredAt = operationTimestamp(operation.date);
+        if (
+          operation.date?.seconds === undefined ||
+          !Number.isFinite(occurredAt.valueOf())
+        )
           throw new Error('Invalid operation timestamp');
         if (
           occurredAt < interval.from ||
@@ -793,12 +792,7 @@ export class BrokerageOperationsRepository {
             if (previous && isDeepStrictEqual(previous.payload, operation))
               continue;
             const data = {
-              occurredAt: new Date(
-                Number(operation.date?.seconds) * MILLISECONDS_PER_SECOND +
-                  Math.floor(
-                    (operation.date?.nanos ?? 0) / NANOSECONDS_PER_MILLISECOND,
-                  ),
-              ),
+              occurredAt: operationTimestamp(operation.date),
               instrumentUid: operation.instrumentUid ?? null,
               category: operationCategory(operation.type),
               payload: row.payload as Prisma.InputJsonObject,