maint: 🔧 update example app when honeycomb-opentelemetry-web files change

[ahrbnsn]

Short description of the changes

Adds dev command to the example app. Builds the source js, starts the server, and watches honeycomb-opentelemtry-web files for any changes. When there's a change, re-builds the example app's js.

How to verify that this has the expected result

• pull the branch down locally.

cd examples/hello-world
npm run dev

• open up the example app in your browser of choice
• make a change to any of the source files in the root directory
• refresh the example app

should be running the new code

[pkanal]

I'm so pumped for this! Going to make dev a lot easier!

[pkanal]

I tried this out locally and made a change in src/honeycomb-otel-sdk.ts and it didn't end up showing up in the app. I can see that it is detecting a change in that file but I think the change isn't showing up because we're not rebuilding at the root level as well as the app level? I don't see the changes rebuilt in the dist folder.

[JamieDanielson]

The updated command works! Couple suggestions but otherwise this is great thanks!

[JamieDanielson]

I think we can keep this because it's still a viable option, just may be preferred to use the dev option in local dev

[ahrbnsn]

i tweaked the npm run start command so it calls npm run build itself, so folks wouldn't have to run both commands before starting up the server

[ahrbnsn]

i'm going to merge, but definitely feel free to ignore & use the current existing setup in your 🔥 local dev instructions in #28