Extract Ladill QR Plus as standalone app at qr.ladill.com.

Utility QR types only (URL, WiFi, link list, business, app download) with
SSO, Billing API integration, public /q resolver, and qr-plus:import for
platform migration. vCard and commerce types stay on the platform.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -0,0 +1,33 @@
+APP_NAME="Ladill QR Plus"
+APP_ENV=production
+APP_KEY=
+APP_DEBUG=false
+APP_URL=https://qr.ladill.com
+
+PLATFORM_URL=https://ladill.com
+PLATFORM_DOMAIN=ladill.com
+AUTH_DOMAIN=auth.ladill.com
+ACCOUNT_DOMAIN=account.ladill.com
+QR_DOMAIN=qr.ladill.com
+
+DB_CONNECTION=mysql
+DB_HOST=127.0.0.1
+DB_PORT=3306
+DB_DATABASE=ladill_qr_plus
+DB_USERNAME=ladill_qr_plus
+DB_PASSWORD=
+
+SESSION_DRIVER=database
+SESSION_LIFETIME=120
+SESSION_DOMAIN=.ladill.com
+
+LADILL_SSO_CLIENT_ID=
+LADILL_SSO_CLIENT_SECRET=
+
+BILLING_API_URL=https://ladill.com/api/billing
+BILLING_API_KEY_QR=
+
+IDENTITY_API_URL=https://ladill.com/api
+IDENTITY_API_KEY_QR=
+
+VITE_APP_NAME="${APP_NAME}"