Allow referencing other apps (#692)

- [x] Update chat_stream_handlers
- [x] Update token handlers
- [x] Update HomeChatInput
- [x] update lexical chat input: do not allow referencing same app
(current app, or other already selected apps)
- [x] I don't think smart context will work on this...
- [x] Enter doesn't clear...

e2e-tests/mention_app.spec.ts

@@ -0,0 +1,21 @@
+import { test } from "./helpers/test_helper";
+
+test("mention app (without pro)", async ({ po }) => {
+  await po.setUp({ autoApprove: true });
+
+  await po.importApp("minimal-with-ai-rules");
+  await po.goToAppsTab();
+  await po.sendPrompt("[dump] @app:minimal-with-ai-rules hi");
+
+  await po.snapshotServerDump("all-messages");
+});
+
+test("mention app (with pro)", async ({ po }) => {
+  await po.setUpDyadPro();
+
+  await po.importApp("minimal-with-ai-rules");
+  await po.goToAppsTab();
+  await po.sendPrompt("[dump] @app:minimal-with-ai-rules hi");
+
+  await po.snapshotServerDump("all-messages");
+});