ccmux v0.2.0

fix: shipped bundle is truly self-contained — stub react-devtools-core at build time so a cache-cleared / offline machine no longer dies on start with ENOENT; + guard test against future hoisted externals

• Fix the shipped bundle silently depending on the global bun cache / npm at startup. ink imports an
  optional DEV-only React DevTools client (react-devtools-core) via a HOISTED static import, so it
  loaded on every launch — and built with --external it resolved that import at runtime against
  ~/.bun/install/cache (or an npm auto-install). A machine whose cache was cleared, or that had no
  network, died on start with ENOENT ... react-devtools-core — the daemon (and every session it
  supervises) down. The "self-contained" bundle was never actually self-contained. The build now
  compiles an inert stub in its place (Bun.build() API + a resolve plugin instead of the
  bun build --external spawn), so the single-file bundle carries no external import and starts
  offline / with an empty cache. The bundling moved to scripts/bundle.ts (one build path shared by
  stage / CI / release), the misleading "never reached in prod" comment and the obsolete "build only
  outside the project tree" caveat are gone, and a guard test builds via that same path and asserts
  the bundle starts under a wiped cache + dead registry — so this can never silently regress.