feat(backend): add /feed endpoint mirrored from /posts

- Introduced FeedModule with controller and service
- /feed mirrors /posts 1:1 (baseline, deterministic)
- No discovery or random logic yet
- Prisma + DI fully wired and stable
- Backend now frontend-ready for feed consumption

backend/src/app.module.ts

@@ -1,17 +1,21 @@
 import { Module } from '@nestjs/common';
 import { APP_GUARD } from '@nestjs/core';
+
 import { PostsModule } from './posts/posts.module';
+import { FeedModule } from './feed/feed.module';
 import { PrismaModule } from './prisma/prisma.module';
+
 import { DummyAuthGuard } from './auth/guards/dummy-auth.guard';
 import { HealthController } from './health.controller';
 
 @Module({
   imports: [
-    PostsModule, // 👈 aktivieren wir jetzt bewusst
-    PrismaModule,
+    PrismaModule, // Basis zuerst
+    PostsModule,  // /posts
+    FeedModule,   // /feed (1:1 Spiegel)
   ],
   controllers: [
-    HealthController, // 👈 bleibt direkt hier
+    HealthController,
   ],
   providers: [
     {

backend/src/feed/feed.controller.ts

@@ -0,0 +1,13 @@
+import { Controller, Get, Req } from '@nestjs/common';
+import { FeedService } from './feed.service';
+import { AuthRequest } from '../auth/types/auth-request';
+
+@Controller('feed')
+export class FeedController {
+  constructor(private readonly feedService: FeedService) {}
+
+  @Get()
+  async getFeed(@Req() req: AuthRequest) {
+    return this.feedService.getFeed(req.user);
+  }
+}

backend/src/feed/feed.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { FeedController } from './feed.controller';
+import { FeedService } from './feed.service';
+import { PrismaService } from '../prisma/prisma.service';
+
+@Module({
+  controllers: [FeedController],
+  providers: [FeedService, PrismaService],
+})
+export class FeedModule {}

backend/src/feed/feed.service.ts

@@ -0,0 +1,24 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+
+type AuthUser = {
+  id: string;
+  role: 'USER' | 'ADMIN' | 'MOD';
+} | null;
+
+@Injectable()
+export class FeedService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getFeed(_user: AuthUser) {
+    return this.prisma.post.findMany({
+      include: {
+        pet: true,
+        author: true,
+      },
+      orderBy: {
+        createdAt: 'desc',
+      },
+    });
+  }
+}