BREAKING CHANGE: Composer packages renamed from arqel/* to arqel-dev/*
and npm packages from @arqel/* to @arqel-dev/*. Consumers must update
their composer.json and package.json. The PHP namespace `Arqel\` is
preserved unchanged. Domain `arqel.dev` is preserved.

- 19 PHP packages renamed in composer manifests + composer.lock regen
- 16 npm packages renamed in package.json + pnpm-lock.yaml regen
- All github.com/arqel/arqel URLs rewritten to github.com/arqel-dev/arqel
  (docs, CI, issue templates, VitePress edit links)
- Meta-package arqel/arqel renamed to arqel-dev/arqel
- Documentation references to future packages (arqel/testing,
  arqel/demo-app, arqel/laravel-cloud-template, arqel/button) updated
- Version bumped from 0.8.0-rc.1 to 0.8.0 across all 36 manifests;
  realtime-collab unified from 0.10.0-rc.1 to 0.8.0
- CHANGELOG entry [0.8.0] documenting the rename
- Release pipeline (.github/workflows/release.yml) replaced placeholder
  with real implementation: splitsh/lite per-package split + push to
  arqel-dev/<pkg> sub-repos (auto-created if missing) + pnpm publish -r
  + GitHub release with notes extracted from CHANGELOG
- docs/publishing-setup.md updated with pre-tag checklist for v0.8.0
- Resolved stale merge conflict markers in apps/demo/composer.json
  (kept laravel/framework dependency, dropped split illuminate/* form)

Composer validate clean, autoload regenerates 4960 classes, pnpm install
clean. Pre-existing typecheck warnings (jest-dom matchers, JSX namespace,
ChartCard prop) are unrelated to this rename.

Signed-off-by: Diogo C. Coutinho <diogo.coutinho.ads@gmail.com>