fix: add variant to User model schema to resolve merge conflict with dev

Both authProfile and variant now exist in the User model, fixing type errors
after merging with anomalyco/dev

packages/opencode/src/session/llm.ts

@@ -152,7 +152,9 @@ export namespace LLM {
     }
 
     const variant =
-      !input.small && runtimeModel.variants && input.user.variant ? runtimeModel.variants[input.user.variant] : {}
+      !input.small && runtimeModel.variants && input.user.model.variant
+        ? runtimeModel.variants[input.user.model.variant]
+        : {}
     const base = input.small
       ? ProviderTransform.smallOptions(runtimeModel)
       : ProviderTransform.options({

packages/opencode/src/session/message-v2.ts

@@ -372,6 +372,7 @@ export namespace MessageV2 {
       providerID: ProviderID.zod,
       modelID: ModelID.zod,
       authProfile: z.string().optional(),
+      variant: z.string().optional(),
     }),
     system: z.string().optional(),
     tools: z.record(z.string(), z.boolean()).optional(),