fix(mac): bundle web chat UI deps

apps/macos/Sources/Clawdis/Resources/WebChat/pi-ai-stub.js

@@ -0,0 +1,24 @@
+// Minimal browser-friendly stub for @mariozechner/pi-ai
+export function getModel(provider, id) {
+  return {
+    provider,
+    id,
+    name: id,
+    api: `${provider}-messages`,
+    input: ["text"],
+    output: ["text"],
+    maxTokens: 200000,
+    reasoning: true,
+    headers: undefined,
+    baseUrl: undefined,
+  };
+}
+
+// Dummy stream helpers used in some debug flows; no-ops in web chat.
+export function agentLoop() {
+  throw new Error("agentLoop is not available in embedded web chat");
+}
+export class AssistantMessageEventStream {
+  push() {}
+  end() {}
+}