ensure_browser() (install.sh) and Install-AgentBrowser (install.ps1)
are reached only via the explicit --ensure browser / -Ensure browser
on-demand mode, itself only triggered by an actual browser-tool call's
lazy-install fallback or `hermes acp --setup-browser`. agent-browser
already resolves via npx in that same fallback before ever reaching
these scripts, so eagerly npm-installing a second, separately
version-pinned copy here was redundant and an extra credential/
supply-chain surface for a path npx already covers. Chromium
acquisition for this on-demand path is now deferred entirely to
_maybe_autoinstall_chromium's existing lazy fallback. camofox's
install and system-browser detection/configuration are unaffected.
install.ps1 also drops the now-dead -SkipChromium switch, confirmed
unused at its one call site.