v0.5.0

• Installer now adds :nstandard to the host project with runtime: false
  (via Igniter's dep_opts). Nstandard only provides installer-time tooling,
  so it never needs to start as an application.
• Bump spellweaver constraint to ~> 0.1.8 (in both the host installer and
  nstandard's own deps). 0.1.7 had a bun add bootstrap bug that made
  mix spellweaver.check fail with a missing priv/bun/package.json.
• Add an integration test that runs mix igniter.new --install nstandard@path:.
  against the working tree and asserts mix check passes end-to-end on the
  generated project. Requires the igniter_new archive to be installed.