Improve error handling when the apphost server has an error

[davidfowl]

Is there's any error running the apphost server (TypeScript scenario) (likely a runtime loading error) then the backchannel ends up hanging for a long time waiting for the backchannel to become active. We need to improve the user experience here.

[MihuBot]

I'm a bot. Here are possible related and/or duplicate issues (I may be wrong):

• Better handle backchannel failures when apphost fails to build/crashes early. #8245
• TypeScript apphost: Time out waiting for AppHost server to start after 60 seconds #14927

[afscrome]

I saw similar issues last night when I first cloned an repo to a new machine, and nuget restore hung - aspire CLI didn't provide great feedback over that, I only identified the issue after dotnet runing the app host.

[JamesNK]

@davidfowl Can you give more details on a repro?

Steps I followed to reproduce this:

1. aspire new -> express app
2. Edit apphost.ts to add a syntax error
3. aspire run
4. Immediately fails with a good exception:

I also tried out what happens if the app host takes a long time to run for some reason by adding a long delay to it, and there is a timeout after 60 seconds. This seems like what we want: