Can we have a --watch option for wxt build

[zouhangwithsweet]

Like:

wxt build --watch

[zouhangwithsweet]

Or we can have a option to disabled dev server reload page.

[aklinker1]

Sure, I can add a watch mode. Would be useful for Firefox MV3 development CC @yunsii

[yunsii]

Good idea, but it is too slow if build every entrypoint with single file, #357 is necessary.