Artifact Registry organization settings area: Rails mount, navigation, and Vue shell (monolith/S01 Steps 5, 5a)

Context

Stand up the Settings organization area for Artifact Registry: a single settings page (Rails mount plus a Settings-menu item) and its Vue sectioned-settings shell. Builds on the shared EE seam (#599226 (closed)).

This issue covers Steps 5 and 5a of the monolith/S01 plan.

Scope

Step 5 - Settings area Rails mount and navigation

  • Settings route .../-/settings/artifact_registry -> Organizations::Settings::ArtifactRegistryController#show, gated via the shared concern, declaring feature_category :artifact_registry, rendering the settings mount view.
  • App-data helper returning the settings mount config as JSON.
  • Add the missing prepend_mod_with seam to the FOSS organizations SettingsMenu, plus an EE override that inserts the flag/permission-gated "Artifacts" settings item via insert_item_after.

Step 5a - Settings area Vue sectioned-settings shell

  • Fresh AR-owned settings bootstrap plus the parent sectioned-settings shell: a vertical stack of independently collapsible sections, search-driven expand/collapse, a shared alert surface, and an empty state, composing the framework-shared SettingsBlock and SearchSettings, with a createDefaultClient Apollo provider. Registers no section content.

Acceptance

  • Flag on + access -> 200 settings mount; flag off / no access -> 404.
  • Flag on + permitted -> the Settings "Artifacts" item renders (guarding the prepend seam); flag off -> the item is hidden.
  • The shell renders registered sections stacked, toggles an individual section's state, expands/collapses on settings search, and renders without error when no sections are registered.

Dependencies

References