This adds source maps to both the dev and production builds. Since this project is open source and downloaded ahead of time, there is not much negative cost to shipping source maps in production, as this can help any developers who encounter bugs related to Angular DevTools on the page.

There is a slight performance cost to both processing the `sourceMappingURL` comment _and_ actually processing the sourcemaps. Ideally, we would use linked sourcemaps all the time, as this avoids processing this and parses only a trivial comment unless the user actually opens a debugger. Unfortunately, Chrome seems to fail to load linked sourcemaps for scripts injected into the user's page (the backend script and content scripts), so these need inlined sourcemaps to work, which somewhat increases the performance cost. These scripts should be small enough to not be a major issue, but we can consider removing them in production based on signal from the community if necessary.