- Two separate cards (register + login) -> single unified card
- handleRegister + handleLogin -> single handleAuth that tries login first,
falls back to register if login fails (new user detection)
- Single email/password input, single button, single status display
- Enter key submits on both fields
- File size 57873 -> 51329 chars (-11%)
Test: test_tksea_portal_assets.sh PASS, verify_frontend_smoke.sh PASS,
verify_quality_gates.sh PASS (gofmt+vet+cov+integration)