[Gogo-Eng]

Summary

Testing

Checklist

• Tests cover the change
• Tests build loans, applicants and milestones with the shared factories in backend/src/test-utils/factories — no inline fixtures for these entities (see docs/TEST_DATA_FACTORIES.md)
• Nothing secret is exposed to the client: new browser-side variables use the NEXT_PUBLIC_ prefix and hold only public values
• Docs updated if behaviour or configuration changed