Replace the host-side `make npm-install` step with a compose-level
`command:` override that runs `npm install` inside the container on
every start. Back node_modules and static/vendor with named volumes so
the bind-mounted source tree no longer shadows the install while state
still survives container restarts. Drop the now-redundant npm-install
target and its references in up/dev/prod/test-e2e.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
