feat: add org admin SPA for models, roles and provider

Introduce admin-web (Skeleton/SvelteKit), Prisma models for provider connection / OrgModel / OrgRole, DB-backed runtime settings, and admin API routes so org admins can manage agent configuration end-to-end.

hub/admin-web/src/app.d.ts

@@ -0,0 +1,13 @@
+// See https://svelte.dev/docs/kit/types#app.d.ts
+// for information about these interfaces
+declare global {
+	namespace App {
+		// interface Error {}
+		// interface Locals {}
+		// interface PageData {}
+		// interface PageState {}
+		// interface Platform {}
+	}
+}
+
+export {};