feat: Add Academy, Whistleblower, Incidents, Vendor, DSB, SSO, Reporting, Multi-Tenant and Industry backends

Go handlers, models, stores and migrations for all SDK modules.
Updates developer portal navigation and BYOEH page.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

developer-portal/components/DevPortalLayout.tsx

@@ -72,6 +72,7 @@ const navigation: NavItem[] = [
     icon: <BookOpen className="w-4 h-4" />,
     items: [
       { title: 'Compliance Service', href: '/development/docs' },
+      { title: 'Klausur-Namespace (BYOEH)', href: '/development/byoeh' },
     ],
   },
   {