Default Sentry Error Monitoring for Frontend

I recently set up a basic ruby on rails project.
e.g.
`rails new blog`

I went to integrate sentry and followed the rails setup https://docs.sentry.io/platforms/ruby/guides/rails/

```Gemfile
gem "stackprof"
gem "sentry-ruby"
gem "sentry-rails"
```

and added
```config/initializers/sentry.rb
Sentry.init do |config|
config.dsn = 'my_dsn'

# get breadcrumbs from logs
config.breadcrumbs_logger = [:active_support_logger, :http_logger]

# enable tracing
# we recommend adjusting this value in production
config.traces_sample_rate = 1.0

# enable profiling
# this is relative to traces_sample_rate
config.profiles_sample_rate = 1.0
end
```

From there, I validated that my endpoints were being covered by Sentry. However, I was completely lost on how to set up monitoring for the frontend side of my project.

We should have a guide / SDK wizard for how to instrument Sentry JS for the default rails app setup (import maps), and additionally how to configure if the user is using node/yarn/bun.

Rails javascript docs:
https://guides.rubyonrails.org/working_with_javascript_in_rails.html

This is all on Rails 7 which is the current prod rails version. I'm not sure how past Rails works or Rails 8 works, but its worth supporting this use case for the current version to start.