Add Dependencies and Dependents tabs to addon details

[raggi]

New Dependencies tab on the addon details view shows per-dependency resolution (installed by an existing addon, satisfied by a manual override, ignored, or unresolved with ranked install suggestions). Each row supports install, ignore, satisfied-by, and revoke actions, with a top-level "Install all" for batch-install of all unresolved suggestions. Suggestions are ranked using the same directory-count / download / date ordering as the global recommender.

New Dependents tab lists installed addons that declare this addon as a dependency, derived from the same addon_dependency table. Both tabs become inert (greyed out, "No Dependencies" / "No Dependents" labels) when empty rather than disappearing.

Adds the supporting types (AddonRef, Resolution, DepStatus, AddonDependencyView) in service::result and the service methods that back the tabs (get_addon_dependency_view, set_dep_ignored, set_dep_satisfied_by, revoke_dep_override, install_dep_suggestions).

Also trigger check_missing_deps directly from handle_addons_changed so the missing-deps sidebar entry clears as soon as the user resolves all missing deps, instead of relying on the installed_addons -> check_missing_deps chain (which only fires after the filesystem walk completes, and never fires at all if install_missing_dependencies hits the unwrap() panic path). handle_addons_changed now kicks off both refreshes in parallel, so the auto-navigate to the MissingDeps view is guarded against installed_addons.value being None — only the modal auto-pop is deferred until both promises have results; the sidebar entry itself updates correctly.

Related

• Best paired with Rank dep recommender suggestions by directory count #431 (recommender ranking) and Detect dependencies from installed addon manifests #432 (manifest dep extraction) to populate the tabs with useful data; works standalone otherwise (empty tabs, fewer suggestions).
• Improve view navigation #433 (view navigation) makes the clickable addon refs in these tabs work correctly when navigating between addons from Details.