Builds out the user-facing docs tree alongside the slice-1 build target.
Kept the implementer's planned Task 7 'Slice 1 dev loop' README section
untouched — these docs are the canonical destination for that pointer.
- docs/QUICKSTART.md: 5-min path to 'hear the echo' (libopus install,
cargo run, browser steps, troubleshooting, what's happening under the
hood).
- docs/DEVELOPMENT.md: dev loop — workspace layout, per-crate iteration,
running tests, the 20 ms loop / 'drop + observe' rule, slice-1
boundaries (what NOT to add yet).
- CONTRIBUTING.md (at repo root, conventional): trunk-based dev,
CI gates, commit message style, atomic commits, code style +
learner-facing documentation policy, terminology policy, PR workflow
+ review checklist, GPL-3.0-or-later license.
- README.md: add a Quickstart pointer at the top, a Documentation table
linking to every doc, and the slice-1 build-target status block.
