Rebuild admin pages around DataTable/AdminModal; restructure categories/groups and v2 groups API

Remove the generic $lib/svelte-admin CRUD layer and AdminTable.svelte; each
admin route now owns its own form/modal logic. Add DataTable.svelte,
superform-errors.ts, and profile-specific modal/field components.

Flatten proclamation categories/groups and drop subscription levels; add the
v2 groups API; update v1/v2 endpoints, serializers, auth, and regenerated
Prisma client with the new migrations.

Document the overhaul plan in docs/ADMIN_OVERHAUL.md.

src/lib/server/v2-signature.spec.ts

@@ -17,7 +17,7 @@ function signedRequest(opts: {
 	const path = '/api/v2/automations/create/account';
 	const timestamp = String(Math.floor((opts.now ?? new Date()).getTime() / 1000));
 	const nonce = 'a48c0f2e-5f34-4b0b-9a12-3c7d6b8e1f00';
-	const body = '{"email":"user@example.com","subscription_level":"Basic"}';
+	const body = '{"email":"user@example.com"}';
 
 	let ts = timestamp;
 	let nonceValue = nonce;