Repo: Update Analog SFC app to use .ag extension instead of .analog extension by default

[brandonroberts]

Which scope/s are relevant/related to the feature request?

Don't know / other

Information

We've added support for the .ag extension when using the Analog SFC. This would update the ng-app in the repo to use the new extension instead.

We're updating the Analog Language Tools and IDEA Plugin to support the extension also.

Describe any alternatives/workarounds you're currently using

No response

I would be willing to submit a PR to fix this issue

• [ ] Yes
• [ ] No