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/auth/presentation/auth.controller.spec.ts

@@ -1,21 +0,0 @@
-import { HTTP_CODE_METADATA } from '@nestjs/common/constants';
-
-jest.mock('../application/auth.service', () => ({
-  AuthService: class AuthService {},
-}));
-
-import { AuthController } from './auth.controller';
-
-describe('AuthController response statuses', () => {
-  it.each(['register', 'login', 'refresh'] as const)(
-    '%s explicitly returns HTTP 200',
-    (handler) => {
-      // Nest stores @HttpCode metadata on the unbound handler function.
-      const handlerTarget = Object.getOwnPropertyDescriptor(
-        AuthController.prototype,
-        handler,
-      )?.value as object;
-      expect(Reflect.getMetadata(HTTP_CODE_METADATA, handlerTarget)).toBe(200);
-    },
-  );
-});

src/modules/auth/presentation/auth.controller.ts

@@ -87,7 +87,7 @@ export class AuthController {
       if (!token) throw new UnauthorizedException({ code: 'UNAUTHORIZED' });
       return this.respond(response, await this.auth.refresh(token));
     } catch (error) {
-      this.clearCookie(response);
+      if (error instanceof UnauthorizedException) this.clearCookie(response);
       throw error;
     }
   }