refactor: move Dispo Import + Skill Import into ACN-Orga submenu

Both import pages are now grouped under the ACN-Orga collapsible
section in the admin sidebar instead of being separate top-level items.

ACN-Orga submenu now contains:
- Countries
- Org Units
- Util. Categories
- Mgmt Levels
- Dispo Import (moved)
- Skill Import (moved)

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/components/layout/AppShell.tsx

@@ -182,16 +182,16 @@ const adminNavEntries: AdminEntry[] = [
       { href: "/admin/org-units", label: "Org Units", icon: <AdminIcon /> },
       { href: "/admin/utilization-categories", label: "Util. Categories", icon: <AdminIcon /> },
       { href: "/admin/management-levels", label: "Mgmt Levels", icon: <AdminIcon /> },
+      { href: "/admin/dispo-imports", label: "Dispo Import", icon: <AdminIcon /> },
+      { href: "/admin/skill-import", label: "Skill Import", icon: <AdminIcon /> },
     ],
   },
   { href: "/admin/calculation-rules", label: "Calc. Rules", icon: <AdminIcon /> },
   { href: "/admin/users", label: "Users", icon: <AdminIcon /> },
   { href: "/admin/system-roles", label: "System Roles", icon: <AdminIcon /> },
   { href: "/admin/settings", label: "Settings", icon: <AdminIcon /> },
-  { href: "/admin/skill-import", label: "Skill Import", icon: <AdminIcon /> },
   { href: "/admin/notifications", label: "Broadcasts", icon: <BroadcastIcon /> },
   { href: "/admin/webhooks", label: "Webhooks", icon: <AdminIcon /> },
-  { href: "/admin/dispo-imports", label: "Dispo Import", icon: <AdminIcon /> },
   { href: "/admin/activity-log", label: "Activity Log", icon: <ActivityLogIcon /> },
 ];