fix: skip ultrawork variant override when SDK validation unavailable

When provider.list is not available for SDK validation, do not apply the configured ultrawork variant. This prevents models without a max variant from being incorrectly forced to max when ultrawork mode activates.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/plugin/ultrawork-model-override.ts

@@ -161,7 +161,10 @@ export function applyUltraworkModelOverrideOnMessage(
     : currentModel
 
   if (!client || typeof (client as { provider?: { list?: unknown } }).provider?.list !== "function") {
-    applyResolvedUltraworkOverride({ override, validatedVariant: override.variant, output, inputAgentName, tui })
+    log("[ultrawork-model-override] SDK validation unavailable, skipping variant override", {
+      variant: override.variant,
+    })
+    applyResolvedUltraworkOverride({ override, validatedVariant: undefined, output, inputAgentName, tui })
     return
   }