fix: persist refresh cookie across browser restarts (WealthLedger/backend#123)

The refresh cookie had no Max-Age, so browsers dropped it on close
while the Session stayed valid for 7 days. Set maxAge from
REFRESH_TTL_MS, the same constant behind Session.expiresAt.

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

@@ -22,7 +22,7 @@ import {
 
 import { ApiProblemResponses } from '../../../common/decorators/api-safe-error-response.decorator';
 import { HttpErrorCode } from '../../../common/error-code';
-import { AuthService } from '../application/auth.service';
+import { AuthService, REFRESH_TTL_MS } from '../application/auth.service';
 import { AccessPayload, AuthenticationResult } from '../application/auth.types';
 import { LoginDto, RegisterDto } from './auth.dto';
 import { JwtAuthGuard } from './jwt-auth.guard';
@@ -134,6 +134,7 @@ export class AuthController {
       sameSite: 'lax' as const,
       secure: process.env['NODE_ENV'] !== 'development',
       path: COOKIE_PATH,
+      maxAge: REFRESH_TTL_MS,
     };
   }
 }