jdjchelp-jpg/nodebpm4b — reverse-engineered prompt

Build me a local app called BPM4B that feels like an all in one audiobook tool for regular people. I want a simple web page I can open in my browser where I can upload an MP3 and turn it into an M4B audiobook, add chapter titles and times, and download the finished file. I also want to upload documents like EPUB, PDF, DOCX, TXT, or Markdown and turn them into an audiobook with text to speech, with voice, language, and playback speed options.

Please include the document to EPUB flow too, so someone can upload a document and get a clean EPUB out. If the project already supports a better narration engine, use the more reliable default one, but keep the faster built in option available. Add a basic editor for checking chapter text, renaming chapters, merging or excluding sections, and previewing boundaries.

It should also work from the command line for the main jobs, and expose simple API endpoints for the same conversions. Look up current docs online if you need to.