fix: use APP_GUARD provider for global authentication guard

- Replace manual guard instantiation with DI-managed APP_GUARD provider
- Fixes request timeout issue caused by improper Passport JWT strategy initialization
- Add @Public() decorator to remaining sync endpoints for public access
- Remove unused Reflector import from main.ts

backend/src/app.module.ts

@@ -1,6 +1,7 @@
 import { Module } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
 import { TypeOrmModule } from '@nestjs/typeorm';
+import { APP_GUARD } from '@nestjs/core';
 import { AppController } from './app.controller';
 import { AppService } from './app.service';
 import { ArticlesModule } from './modules/articles.module';
@@ -23,6 +24,7 @@ import {
 } from './modules/entities';
 import { ShareEvent } from './modules/analytics/analytics.entity';
 import { PushSubscriptionEntity } from './modules/push/push-subscription.entity';
+import { JwtAuthPublicGuard } from './modules/auth/jwt-auth-public.guard';
 
 @Module({
   imports: [
@@ -61,6 +63,12 @@ import { PushSubscriptionEntity } from './modules/push/push-subscription.entity'
     PushModule,
   ],
   controllers: [AppController],
-  providers: [AppService],
+  providers: [
+    AppService,
+    {
+      provide: APP_GUARD,
+      useClass: JwtAuthPublicGuard,
+    },
+  ],
 })
 export class AppModule {}

backend/src/main.ts

@@ -1,7 +1,6 @@
-import { NestFactory, Reflector } from '@nestjs/core';
+import { NestFactory } from '@nestjs/core';
 import { ValidationPipe } from '@nestjs/common';
 import { AppModule } from './app.module';
-import { JwtAuthPublicGuard } from './modules/auth/jwt-auth-public.guard';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
@@ -36,10 +35,6 @@ async function bootstrap() {
     }),
   );
 
-  // Apply global authentication guard
-  const reflector = app.get(Reflector);
-  app.useGlobalGuards(new JwtAuthPublicGuard(reflector));
-
   const port = process.env.PORT ?? 3000;
   const host = '0.0.0.0'; // Bind to all interfaces for Docker
   await app.listen(port, host);

backend/src/modules/strapi.controller.ts

@@ -134,12 +134,14 @@ export class StrapiController {
   }
 
   @Post('sync/live-blogs')
+  @Public()
   async syncAllLiveBlogs() {
     await this.strapiService.syncLiveBlogs();
     return { message: 'Live blogs sync completed' };
   }
 
   @Post('sync/everything')
+  @Public()
   async syncEverything() {
     await Promise.all([
       this.strapiService.syncArticles(),