Use parsed Claude models and remove auto defaults

packages/app/src/utils/extract-agent-model.test.ts

@@ -20,12 +20,12 @@ describe("extractAgentModel", () => {
     expect(extractAgentModel(agent)).toBe("gpt-5.1-codex");
   });
 
-  it("treats legacy 'default' model ids as unset", () => {
+  it("preserves 'default' as a valid model id", () => {
     const agent = {
       model: "default",
       runtimeInfo: { model: "default" },
     } as Partial<Agent> as Agent;
 
-    expect(extractAgentModel(agent)).toBeNull();
+    expect(extractAgentModel(agent)).toBe("default");
   });
 });

packages/app/src/utils/extract-agent-model.ts

@@ -6,13 +6,13 @@ export function extractAgentModel(agent?: Agent | null): string | null {
   const fallbackModel = agent.model;
   if (typeof runtimeModel === "string") {
     const normalized = runtimeModel.trim();
-    if (normalized.length > 0 && normalized.toLowerCase() !== "default") {
+    if (normalized.length > 0) {
       return normalized;
     }
   }
   if (typeof fallbackModel === "string") {
     const normalized = fallbackModel.trim();
-    if (normalized.length > 0 && normalized.toLowerCase() !== "default") {
+    if (normalized.length > 0) {
       return normalized;
     }
   }