Adds docs/quickstart.md — a step-by-step, no-experience-assumed walkthrough
from installing the build tools to the first coli chat, with per-OS
copy-paste commands (Ubuntu apt, Windows MSYS2 or prebuilt binary, macOS
brew), the ready-made HF int4 container plus the self-convert path, and an
honest 'what to expect' on disk-bound speed. Commands verified against
setup.sh and the coli subcommands; every cross-linked doc exists. Linked
from the README's Get started section.
Closes#414
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
JustVugg