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);
+  }
+}