docs(features): update lesson-management feature document with completed Phase 1 tasks

- Marked Phase 1: Database & Models as COMPLETED
- Updated all Phase 1 tasks as completed
- Updated Backend and Database task checkmarks

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

docs/features/lesson-management.md

@@ -10,6 +10,8 @@
 > **PR**: -  
 > **Related Features**: Infrastructure Setup, User Authentication, Vocabulary System, Quiz System, Story Integration
 
+**Phase 1: Database & Models - COMPLETED ✅**
+
 ---
 
 ## 📌 Overview
@@ -132,12 +134,12 @@ Each lesson contains:
 ## 🚀 Implementation Plan
 
 ### Phase 1: Database & Models (2-3 hours)
-- [ ] Create Level entity and repository
-- [ ] Create Lesson entity and repository
-- [ ] Create UserProgress entity and repository
-- [ ] Set up relationships between entities
-- [ ] Create migrations for Levels, Lessons, UserProgress
-- [ ] Seed initial A1 level and lessons
+- [x] Create Level entity and repository
+- [x] Create Lesson entity and repository
+- [x] Create UserProgress entity and repository
+- [x] Set up relationships between entities
+- [x] Create migrations for Levels, Lessons, UserProgress
+- [x] Seed initial A1 level and lessons
 
 ### Phase 2: Backend Services (3-5 hours)
 - [ ] Create LevelService with CRUD operations
@@ -180,16 +182,16 @@ Each lesson contains:
 ## ✅ Tasks
 
 ### Backend
-- [ ] Create Domain/Entities/Level.cs
-- [ ] Create Domain/Entities/Lesson.cs
-- [ ] Create Domain/Entities/UserProgress.cs
-- [ ] Create Domain/Interfaces/ILevelRepository.cs
-- [ ] Create Domain/Interfaces/ILessonRepository.cs
-- [ ] Create Infrastructure/Data/Repositories/LevelRepository.cs
-- [ ] Create Infrastructure/Data/Repositories/LessonRepository.cs
-- [ ] Create Infrastructure/Data/Repositories/UserProgressRepository.cs
-- [ ] Create Application/DTOs/LevelDto.cs
-- [ ] Create Application/DTOs/LessonDto.cs
+- [x] Create Domain/Entities/Level.cs
+- [x] Create Domain/Entities/Lesson.cs
+- [x] Create Domain/Entities/UserProgress.cs
+- [x] Create Domain/Interfaces/ILevelRepository.cs
+- [x] Create Domain/Interfaces/ILessonRepository.cs
+- [x] Create Infrastructure/Data/Repositories/LevelRepository.cs
+- [x] Create Infrastructure/Data/Repositories/LessonRepository.cs
+- [x] Create Infrastructure/Data/Repositories/UserProgressRepository.cs
+- [x] Create Application/DTOs/LevelDto.cs
+- [x] Create Application/DTOs/LessonDto.cs
 - [ ] Create Application/DTOs/UserProgressDto.cs
 - [ ] Create Application/Services/LevelService.cs
 - [ ] Create Application/Services/LessonService.cs
@@ -201,11 +203,11 @@ Each lesson contains:
 - [ ] Write integration tests for controllers
 
 ### Database
-- [ ] Create migration for Levels table
-- [ ] Create migration for Lessons table
-- [ ] Create migration for UserProgress table
-- [ ] Seed A1 level with initial lessons
-- [ ] Add indexes for performance
+- [x] Create migration for Levels table
+- [x] Create migration for Lessons table
+- [x] Create migration for UserProgress table
+- [x] Seed A1 level with initial lessons
+- [x] Add indexes for performance
 
 ### Business Logic
 - [ ] Implement LessonUnlockService