feat(auth): implement user authentication with JWT and NextAuth

- Added user registration and login functionality with JWT authentication.
- Created auth controller, service, and module in the backend.
- Implemented user model and user products management.
- Integrated NextAuth for session management on the frontend.
- Added middleware for protecting routes and handling public access.
- Updated frontend API routes to include authorization headers.
- Enhanced recipe and user product models to support ownership and visibility.
- Created registration and login pages in the frontend.
- Added necessary types for NextAuth session management.

backend/src/user-products/dto/upsert-user-product.dto.ts

@@ -0,0 +1,22 @@
+import { IsInt, IsString, IsOptional, IsBoolean } from 'class-validator';
+
+export class UpsertUserProductDto {
+  @IsInt()
+  productId: number;
+
+  @IsOptional()
+  @IsString()
+  note?: string;
+
+  @IsOptional()
+  @IsString()
+  preferredBrand?: string;
+
+  @IsOptional()
+  @IsString()
+  preferredStore?: string;
+
+  @IsOptional()
+  @IsBoolean()
+  isPrivate?: boolean;
+}

backend/src/user-products/user-products.controller.ts

@@ -0,0 +1,38 @@
+import {
+  Controller,
+  Get,
+  Post,
+  Delete,
+  Body,
+  Param,
+  ParseIntPipe,
+} from '@nestjs/common';
+import { UserProductsService } from './user-products.service';
+import { UpsertUserProductDto } from './dto/upsert-user-product.dto';
+import { CurrentUser } from '../auth/decorators/current-user.decorator';
+
+@Controller('user-products')
+export class UserProductsController {
+  constructor(private readonly service: UserProductsService) {}
+
+  @Get()
+  findAll(@CurrentUser() user: { userId: number }) {
+    return this.service.findAll(user.userId);
+  }
+
+  @Post()
+  upsert(
+    @CurrentUser() user: { userId: number },
+    @Body() dto: UpsertUserProductDto,
+  ) {
+    return this.service.upsert(user.userId, dto);
+  }
+
+  @Delete(':productId')
+  remove(
+    @CurrentUser() user: { userId: number },
+    @Param('productId', ParseIntPipe) productId: number,
+  ) {
+    return this.service.remove(user.userId, productId);
+  }
+}

backend/src/user-products/user-products.module.ts

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+import { Module } from '@nestjs/common';
+import { UserProductsController } from './user-products.controller';
+import { UserProductsService } from './user-products.service';
+import { PrismaModule } from '../prisma/prisma.module';
+
+@Module({
+  imports: [PrismaModule],
+  controllers: [UserProductsController],
+  providers: [UserProductsService],
+})
+export class UserProductsModule {}

backend/src/user-products/user-products.service.ts

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+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { UpsertUserProductDto } from './dto/upsert-user-product.dto';
+
+const PRODUCT_INCLUDE = {
+  product: {
+    include: {
+      nutrition: true,
+      tags: { include: { tag: true } },
+    },
+  },
+};
+
+@Injectable()
+export class UserProductsService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  findAll(userId: number) {
+    return this.prisma.userProduct.findMany({
+      where: { userId },
+      include: PRODUCT_INCLUDE,
+      orderBy: { updatedAt: 'desc' },
+    });
+  }
+
+  findOne(userId: number, productId: number) {
+    return this.prisma.userProduct.findUnique({
+      where: { userId_productId: { userId, productId } },
+      include: PRODUCT_INCLUDE,
+    });
+  }
+
+  upsert(userId: number, dto: UpsertUserProductDto) {
+    const { productId, ...data } = dto;
+    return this.prisma.userProduct.upsert({
+      where: { userId_productId: { userId, productId } },
+      create: { userId, productId, ...data },
+      update: data,
+      include: PRODUCT_INCLUDE,
+    });
+  }
+
+  remove(userId: number, productId: number) {
+    return this.prisma.userProduct.delete({
+      where: { userId_productId: { userId, productId } },
+    });
+  }
+}