feat: wire GHL webhook to Resend email templates

- Replace raw Resend text emails with sendMail using Resend templates
- automated-user-registration template: firstName, tempPassword,
  verifyUrl, loginUrl
- license-key-delivery template: firstName, license_key
- Remove requestPasswordReset call (temp password is the one-time
  credential; verification link handles email confirmation)
- Add .catch() to Better Auth email callbacks to prevent unhandled
  rejections from missing templates crashing the server

src/lib/auth.ts

@@ -17,6 +17,8 @@ export const auth = betterAuth({
 			void sendVerificationEmail({
 				email: user.email,
 				token
+			}).catch((e) => {
+				console.error('sendVerificationEmail template email failed:', e);
 			});
 		}
 	},
@@ -31,6 +33,8 @@ export const auth = betterAuth({
 					target_email_address: user.email,
 					reset_link: url
 				}
+			}).catch((e) => {
+				console.error('sendResetPassword template email failed:', e);
 			});
 		}
 	},