feat: public GET /manifest.json from tenant branding

Serve PWA/APK web manifest per domain (name, theme colors, multi-size icons from avatar), exclude from api prefix, and proxy via nginx.

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

src/get-manifest/get-manifest.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { GetUserModule } from '../get-user/get-user.module';
+import { GetManifestController } from './get-manifest.controller';
+
+@Module({
+  imports: [GetUserModule],
+  controllers: [GetManifestController],
+})
+export class GetManifestModule {}