Provider-specific options vanish silently under multi-model wrappers; Sentry's…

Provider-specific options vanish silently under multi-model wrappers; Sentry's JavaScript SDK bug shows the failure mode: the chat still worked but its per-chat config was dropped from traces, hiding why the model behaved that way. The engineering fix is fine, but the design lesson is narrow: add provider-level, wire-oriented contract tests and a conformance suite for each model client before you build another abstraction around them. Those tests should exercise the actual request shape and the proxying paths so options can never be silently thrown away.