When DashCaddy is installed without `${DASHBOARD_DIR}:/app/dashboard` bind
mounted into the container (e.g. legacy DNS2 setup where Caddy serves from
/var/www/dashcaddy-status/), the self-updater's in-container copy to
/app/dashboard was a silent no-op — leaving the dashboard stale across
self-updates, which led to CSP-hash mismatches and a broken UI.
- self-updater: new hostFrontendDir option (default `/var/www/dashcaddy-status`
on Linux, overridable via DASHCADDY_HOST_FRONTEND_DIR). When set, defer the
frontend copy to the host-side updater by passing frontendStagingDir +
frontendTargetDir in trigger.json. Now also includes `js/` in the copy list.
- dashcaddy-update.sh: read those new trigger fields and sync the dashboard
files on the host. Auto-detect fallback for older self-updaters (no fields
in trigger.json) so a single release upgrade self-heals.