Deterministic, change-detecting Bun asset builder for Phoenix.

This package is primarily an Igniter installer plus a build script template. Unlike esbuild/tailwind (which are thin installer+runner wrappers around a generic, flag-driven CLI), the reusable value here is build logic that the bun build CLI cannot express:

• Change-detecting writes — a served bundle is written only when its bytes actually change, so identical rebuilds push zero live-reload events.
• Deterministic output — Bun builds into a fixed staging dir so the inline-sourcemap sources prefix is stable across rebuilds; change detection then reliably suppresses no-op writes.
• Orphan hygiene — the watcher exits on stdin EOF (its Erlang port closing) and reaps stale predecessors via a pidfile, so abnormally-killed dev servers never leak background bundlers.

Because that logic is a JavaScript program (it depends on Bun's Bun.build JS API — result.outputs, arrayBuffer(), Bun.file, Bun.write, Bun.stdin), it is delivered as a build.ts template copied into the target project rather than hidden behind a System.cmd runner. The bun Hex package installs and manages the actual bun binary.

Install with:

mix igniter.install phoenix_bun_assets

See Mix.Tasks.PhoenixBunAssets.Install and the README for details.