fix: license key not showing in email when created via admin page

Problem:
The admin createKey action had two issues preventing the license key from
appearing in the delivery email:

1. Wrong variable name: passed 'licenseKey' (camelCase) but the Resend
   template expects 'license_key' (snake_case).

2. Wrong template: used the default RESEND_TEMPLATE_ID (a generic
   template) instead of the 'license-key-delivery' template that the
   automation endpoint uses for license key emails.

Solution:
- Changed template variable from 'licenseKey' to 'license_key'
- Added explicit templateId: 'license-key-delivery' to match the
  automation endpoint (api/v1/automations/create/account)
- Updated email subject to 'Your Rhemawave License Key' for consistency

Tests:
Added page.server.spec.ts for the admin license-keys createKey action
covering: unauthenticated rejection, missing email/level validation,
user-not-found error, successful key creation with correct template ID
and license_key variable, fallback to user.name when profile is missing,
and graceful handling when email sending fails.

src/routes/(protected)/admin/license-keys/+page.server.ts

@@ -60,10 +60,11 @@ export const actions = {
 			const profile = await prisma.profile.findUnique({ where: { userId: user.id } });
 			await sendMail({
 				to: email,
-				subject: 'Your License Key',
+				subject: 'Your Rhemawave License Key',
+				templateId: 'license-key-delivery',
 				data: {
 					firstName: profile?.firstName ?? user.name ?? 'Valued Customer',
-					licenseKey: key
+					license_key: key
 				}
 			});
 		} catch (e) {