Persist Extensions on launch

```jsonc
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"name": "Hello",
"type": "firefox",
"request": "launch",
"reAttach": true,
"url": "http://localhost:4000/",
}
]
}

```

Under launch mode, a fresh Firefox instance is opened, one with no account synced and no extensions.
Is there an override or anything of some sort that lets "launch" launch a browser instance that's just like a regular launch with remote debugging enabled?

No source file or test is named. Start by tracing how launch configurations create a fresh Firefox instance and handle the reAttach option; done means launch can use a regular Firefox profile with synced account state and extensions while retaining remote debugging, with the behavior covered by an appropriate test.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.