Adds `install.sh --dev` (and MOSAIC_DEV=1): instead of installing
@mosaicstack/mosaic from the registry @latest, download the monorepo archive
at --ref, `pnpm install` + build, `pnpm pack` both @mosaicstack/mosaic and
@mosaicstack/gateway, and `npm install -g` both local tarballs. ZERO registry
writes — no dev dist-tags. Workspace deps resolve from the registry at the
versions `pnpm pack` rewrites `workspace:*` into.
Exports MOSAIC_GATEWAY_SKIP_NPM_INSTALL=1 so the auto-launched wizard keeps the
source-built global gateway instead of overwriting it with the registry build.
Refactors the archive download into a shared ensure_monorepo helper reused by
both the framework install (Part 1) and the dev build (Part 2).
Lets a branch be tested end-to-end on a clean machine before cutting a release,
reducing semver churn.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RMoEx7hfdFGjUiCHuN1RRi
745b9c4967