* test(usage): reproduce quota loss from malformed provider names

* fix(usage): preserve quotas with malformed provider names

Harden optional display-name handling against structured CLI values:
only truthy scalars win the display-name fallback chain, and only
scalars reach String() in providerTitle(). A malformed displayName or
title now degrades to the bundled provider name instead of throwing
inside ToPrimitive and discarding the whole provider snapshot.

Tests: test_provider_title_metadata (10 pass), make check OK.