Add partner SMS gateway via Gama SendQuick and document it.

Expose POST /public/sms/send with API key + domain allowlist for external backends like Balout, wire Meshkee OTP/message sends to Gama, and publish Partner SMS docs on /docs/website.

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

src/app.module.ts

@@ -34,6 +34,7 @@ import { InternalSslModule } from './internal-ssl/internal-ssl.module';
 import { WebsiteDocsModule } from './website-docs/website-docs.module';
 import { InvoicesModule } from './invoices/invoices.module';
 import { LegacyMysqlModule } from './legacy-mysql/legacy-mysql.module';
+import { PublicSmsModule } from './public-sms/public-sms.module';
 
 @Module({
   imports: [
@@ -72,6 +73,7 @@ import { LegacyMysqlModule } from './legacy-mysql/legacy-mysql.module';
     WebsiteModule,
     WebsiteDocsModule,
     InvoicesModule,
+    PublicSmsModule,
   ],
 })
 export class AppModule {}