Bun runtime setup added to Sentry docs

Developers using the Bun runtime no longer have to wrestle with local environment crashes when configuring Sentry error tracking. The friction stems from esbuild handling of the Sentry Node package CommonJS entry, which previously tripped up the local development loop. The documentation now details exactly how to sidestep this by marking the package as external for local development while keeping the standard bundling behavior for deployment. This addition to the guides ensures Bun users can trace errors just as easily as those on standard Node environments.