BBS::FakeOS is a generic, teletype-style engine for simulating retro
operating systems: a scripted boot sequence (BIOS POST, memory test,
banners, typewriter output) followed by an interactive command shell.
Each simulated OS (MS-DOS, CP/M, AmigaDOS CLI, ...) is just a
FakeOS.define { ... } config — prompt, colors, boot block, command table
and an on_unknown fallback — so new OSes are added as configuration, not
code. on_unknown is the natural hook for a conversational/LLM-backed
shell. Exposed as a Flow step (`os <definition>`) alongside tui/app.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
