Adopt Documentation links in widget/page Actions menus (nc-vue#447)

[rubenvdlinde]

Adopt Documentation links in the Actions menu

@conduction/nextcloud-vue now ships a built-in Documentation entry in the shared … Actions menu (the new CnActionsMenu) on widgets and pages, alongside Refresh and Request-a-feature. It opens an app-provided URL in a new tab. Shipped in ConductionNL/nextcloud-vue#447 (on beta).

It's fully opt-in — nothing changes until this app supplies the links.

What to do

1. Bump @conduction/nextcloud-vue to the beta that includes #447.
2. Pass :documentation-url (and optionally :documentation-label) on the surfaces this app renders, pointing at the relevant page on this app's docs site (e.g. https://<app>.conduction.nl/...):
   • CnWidgetWrapper — per dashboard widget (:documentation-url="widget.documentationUrl").
   • CnDetailPage / CnDashboardPage — page-level (:documentation-url, on by default).
   • CnIndexPage / CnActionsBar — list pages (:documentation-url).

Acceptance

• Widgets/pages that have a relevant docs page expose a Documentation item that opens the doc in a new tab.
• No regressions where no URL is supplied.

Tracking the fleet rollout of nc-vue#447.