fix(paseo-agent): use working OAuth catalog model

Live proof showed the previous OAuth catalog default was rejected at session start. Switch the catalog, docs, fixtures, and regenerated schema to the working default while keeping provider config generic.

packages/protocol/src/messages.paseo-agent-config.test.ts

@@ -219,7 +219,7 @@ describe("Paseo Agent config RPC schemas", () => {
       name: "chatgpt",
       providerType: "openai-codex",
       options: {
-        models: [{ id: "gpt-5.3-codex", reasoning: true }],
+        models: [{ id: "gpt-5.4-mini", reasoning: true }],
       },
     });