feat: add course catalog, enrollment, progress tracking, quizzes, and reviews

Backend changes:
- Add Enrollment and LessonProgress models to track user progress
- Add UserRole enum (USER, MODERATOR, ADMIN)
- Add course verification and moderation fields
- New CatalogModule: public course browsing, publishing, verification
- New EnrollmentModule: enroll, progress tracking, quiz submission, reviews
- Add quiz generation endpoint to LessonsController

Frontend changes:
- Redesign course viewer: proper course UI with lesson navigation, progress bar
- Add beautiful typography styles for course content (prose-course)
- Fix first-login bug with token exchange retry logic
- New pages: /catalog (public courses), /catalog/[id] (course details), /learning (enrollments)
- Add LessonQuiz component with scoring and results
- Update sidebar navigation: add Catalog and My Learning links
- Add publish/verify buttons in course editor
- Integrate enrollment progress tracking with backend

All courses now support: sequential progression, quiz tests, reviews, ratings,
author verification badges, and full marketplace publishing workflow.

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

apps/api/src/catalog/catalog.controller.ts

@@ -0,0 +1,46 @@
+import { Controller, Get, Post, Patch, Param, Query, HttpCode, HttpStatus } from '@nestjs/common';
+import { ApiTags, ApiOperation, ApiBearerAuth, ApiQuery } from '@nestjs/swagger';
+import { CatalogService } from './catalog.service';
+import { CurrentUser } from '../auth/decorators/current-user.decorator';
+import { Public } from '../auth/decorators/public.decorator';
+import { User } from '@coursecraft/database';
+
+@ApiTags('catalog')
+@Controller('catalog')
+export class CatalogController {
+  constructor(private catalogService: CatalogService) {}
+
+  @Public()
+  @Get()
+  @ApiOperation({ summary: 'Browse published courses (public)' })
+  async browseCourses(
+    @Query('page') page?: number,
+    @Query('limit') limit?: number,
+    @Query('search') search?: string,
+    @Query('difficulty') difficulty?: string,
+  ): Promise<any> {
+    return this.catalogService.getPublishedCourses({ page, limit, search, difficulty });
+  }
+
+  @Public()
+  @Get(':id')
+  @ApiOperation({ summary: 'Get public course details' })
+  async getCourse(@Param('id') id: string): Promise<any> {
+    return this.catalogService.getPublicCourse(id);
+  }
+
+  @Post(':id/submit')
+  @ApiBearerAuth()
+  @HttpCode(HttpStatus.OK)
+  @ApiOperation({ summary: 'Submit course for review / publish' })
+  async submitForReview(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
+    return this.catalogService.publishCourse(id, user.id);
+  }
+
+  @Patch(':id/verify')
+  @ApiBearerAuth()
+  @ApiOperation({ summary: 'Toggle author verification badge' })
+  async toggleVerify(@Param('id') id: string, @CurrentUser() user: User): Promise<any> {
+    return this.catalogService.toggleVerification(id, user.id);
+  }
+}

apps/api/src/catalog/catalog.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { CatalogController } from './catalog.controller';
+import { CatalogService } from './catalog.service';
+
+@Module({
+  controllers: [CatalogController],
+  providers: [CatalogService],
+  exports: [CatalogService],
+})
+export class CatalogModule {}

apps/api/src/catalog/catalog.service.ts

@@ -0,0 +1,122 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../common/prisma/prisma.service';
+import { CourseStatus } from '@coursecraft/database';
+
+@Injectable()
+export class CatalogService {
+  constructor(private prisma: PrismaService) {}
+
+  async getPublishedCourses(options?: {
+    page?: number;
+    limit?: number;
+    category?: string;
+    difficulty?: string;
+    search?: string;
+  }): Promise<any> {
+    const page = options?.page || 1;
+    const limit = options?.limit || 20;
+    const skip = (page - 1) * limit;
+
+    const where: any = {
+      status: CourseStatus.PUBLISHED,
+      isPublished: true,
+    };
+    if (options?.category) where.categoryId = options.category;
+    if (options?.difficulty) where.difficulty = options.difficulty;
+    if (options?.search) {
+      where.OR = [
+        { title: { contains: options.search, mode: 'insensitive' } },
+        { description: { contains: options.search, mode: 'insensitive' } },
+      ];
+    }
+
+    const [courses, total] = await Promise.all([
+      this.prisma.course.findMany({
+        where,
+        include: {
+          author: { select: { id: true, name: true, avatarUrl: true } },
+          _count: { select: { chapters: true, reviews: true, enrollments: true } },
+          chapters: { include: { _count: { select: { lessons: true } } } },
+        },
+        orderBy: { createdAt: 'desc' },
+        skip,
+        take: limit,
+      }),
+      this.prisma.course.count({ where }),
+    ]);
+
+    const data = courses.map((c) => ({
+      id: c.id,
+      title: c.title,
+      description: c.description,
+      slug: c.slug,
+      coverImage: c.coverImage,
+      price: c.price,
+      currency: c.currency,
+      difficulty: c.difficulty,
+      estimatedHours: c.estimatedHours,
+      tags: c.tags,
+      isVerified: c.isVerified,
+      averageRating: c.averageRating,
+      enrollmentCount: c._count.enrollments,
+      reviewCount: c._count.reviews,
+      chaptersCount: c._count.chapters,
+      lessonsCount: c.chapters.reduce((acc, ch) => acc + ch._count.lessons, 0),
+      author: c.author,
+      publishedAt: c.publishedAt,
+    }));
+
+    return { data, meta: { page, limit, total, totalPages: Math.ceil(total / limit) } };
+  }
+
+  async getPublicCourse(courseId: string): Promise<any> {
+    return this.prisma.course.findFirst({
+      where: { id: courseId, status: CourseStatus.PUBLISHED, isPublished: true },
+      include: {
+        author: { select: { id: true, name: true, avatarUrl: true } },
+        chapters: {
+          include: {
+            lessons: { select: { id: true, title: true, order: true, durationMinutes: true }, orderBy: { order: 'asc' } },
+          },
+          orderBy: { order: 'asc' },
+        },
+        reviews: {
+          where: { isApproved: true },
+          include: { user: { select: { id: true, name: true, avatarUrl: true } } },
+          orderBy: { createdAt: 'desc' },
+          take: 20,
+        },
+        _count: { select: { reviews: true, enrollments: true } },
+      },
+    });
+  }
+
+  async submitForReview(courseId: string, userId: string): Promise<any> {
+    return this.prisma.course.update({
+      where: { id: courseId, authorId: userId },
+      data: { status: CourseStatus.PENDING_REVIEW },
+    });
+  }
+
+  async publishCourse(courseId: string, userId: string): Promise<any> {
+    return this.prisma.course.update({
+      where: { id: courseId, authorId: userId },
+      data: {
+        status: CourseStatus.PUBLISHED,
+        isPublished: true,
+        publishedAt: new Date(),
+      },
+    });
+  }
+
+  async toggleVerification(courseId: string, userId: string): Promise<any> {
+    const course = await this.prisma.course.findFirst({
+      where: { id: courseId, authorId: userId },
+    });
+    if (!course) return null;
+    return this.prisma.course.update({
+      where: { id: courseId },
+      data: { isVerified: !course.isVerified },
+    });
+  }
+}