fix(app): model selection persist by session (#17348)

packages/app/src/pages/session/session-model-helpers.ts

@@ -1,48 +1,16 @@
 import type { UserMessage } from "@opencode-ai/sdk/v2"
-import { batch } from "solid-js"
 
 type Local = {
-  agent: {
-    current():
-      | {
-          model?: UserMessage["model"]
-          variant?: string
-        }
-      | undefined
-    set(name: string | undefined): void
-  }
-  model: {
-    set(model: UserMessage["model"] | undefined): void
-    current():
-      | {
-          id: string
-          provider: { id: string }
-        }
-      | undefined
-    variant: {
-      set(value: string | undefined): void
-    }
+  session: {
+    reset(): void
+    restore(msg: UserMessage): void
   }
 }
 
 export const resetSessionModel = (local: Local) => {
-  const agent = local.agent.current()
-  if (!agent) return
-  batch(() => {
-    local.model.set(agent.model)
-    local.model.variant.set(agent.variant)
-  })
+  local.session.reset()
 }
 
 export const syncSessionModel = (local: Local, msg: UserMessage) => {
-  batch(() => {
-    local.agent.set(msg.agent)
-    local.model.set(msg.model)
-  })
-
-  const model = local.model.current()
-  if (!model) return
-  if (model.provider.id !== msg.model.providerID) return
-  if (model.id !== msg.model.modelID) return
-  local.model.variant.set(msg.variant)
+  local.session.restore(msg)
 }