feat: add A2-B1 course expansion features including listening activities and conversation sessions

- Updated VocabCourseView.vue to display CEFR level for courses.
- Enhanced VocabLessonView.vue with new sections for listening activities and conversation labs, including audio controls and transcript toggling.
- Created migration to add new columns to vocab_course and new tables for conversation sessions and listening activities.
- Implemented models for vocab_conversation_session and vocab_listening_activity.
- Developed scripts to create new A2 and B1 bridge courses with structured lesson plans.
- Documented the A2-B1 expansion plan detailing course structure, learning goals, and assessment criteria.

backend/models/associations.js

@@ -128,6 +128,8 @@ import VocabGrammarExerciseType from './community/vocab_grammar_exercise_type.js
 import VocabGrammarExercise from './community/vocab_grammar_exercise.js';
 import VocabGrammarExerciseProgress from './community/vocab_grammar_exercise_progress.js';
 import VocabSrsItem from './community/vocab_srs_item.js';
+import VocabConversationSession from './community/vocab_conversation_session.js';
+import VocabListeningActivity from './community/vocab_listening_activity.js';
 import CalendarEvent from './community/calendar_event.js';
 import Campaign from './match3/campaign.js';
 import Match3Level from './match3/level.js';
@@ -1188,6 +1190,13 @@ export default function setupAssociations() {
   VocabCourse.hasMany(VocabSrsItem, { foreignKey: 'courseId', as: 'srsItems' });
   VocabSrsItem.belongsTo(VocabCourseLesson, { foreignKey: 'lessonId', as: 'lesson' });
   VocabCourseLesson.hasMany(VocabSrsItem, { foreignKey: 'lessonId', as: 'srsItems' });
+
+  VocabConversationSession.belongsTo(User, { foreignKey: 'userId', as: 'user' });
+  User.hasMany(VocabConversationSession, { foreignKey: 'userId', as: 'vocabConversationSessions' });
+  VocabConversationSession.belongsTo(VocabCourseLesson, { foreignKey: 'lessonId', as: 'lesson' });
+  VocabCourseLesson.hasMany(VocabConversationSession, { foreignKey: 'lessonId', as: 'conversationSessions' });
+  VocabListeningActivity.belongsTo(VocabCourseLesson, { foreignKey: 'lessonId', as: 'lesson' });
+  VocabCourseLesson.hasMany(VocabListeningActivity, { foreignKey: 'lessonId', as: 'listeningActivities' });
   
   // Calendar associations
   CalendarEvent.belongsTo(User, { foreignKey: 'userId', as: 'user' });

backend/models/community/vocab_conversation_session.js

@@ -0,0 +1,25 @@
+import { Model, DataTypes } from 'sequelize';
+import { sequelize } from '../../utils/sequelize.js';
+
+class VocabConversationSession extends Model {}
+
+VocabConversationSession.init({
+  id: { type: DataTypes.INTEGER, primaryKey: true, autoIncrement: true },
+  userId: { type: DataTypes.INTEGER, allowNull: false, field: 'user_id' },
+  lessonId: { type: DataTypes.INTEGER, allowNull: false, field: 'lesson_id' },
+  scenario: { type: DataTypes.JSONB, allowNull: false, defaultValue: {} },
+  turns: { type: DataTypes.JSONB, allowNull: false, defaultValue: [] },
+  summary: { type: DataTypes.JSONB, allowNull: true },
+  status: { type: DataTypes.TEXT, allowNull: false, defaultValue: 'active' },
+  createdAt: { type: DataTypes.DATE, allowNull: false, defaultValue: DataTypes.NOW, field: 'created_at' },
+  updatedAt: { type: DataTypes.DATE, allowNull: false, defaultValue: DataTypes.NOW, field: 'updated_at' }
+}, {
+  sequelize,
+  modelName: 'VocabConversationSession',
+  tableName: 'vocab_conversation_session',
+  schema: 'community',
+  timestamps: true,
+  underscored: true
+});
+
+export default VocabConversationSession;

backend/models/community/vocab_course.js

@@ -39,6 +39,22 @@ VocabCourse.init({
         defaultValue: 1,
         field: 'difficulty_level'
     },
+    cefrLevel: {
+        type: DataTypes.TEXT,
+        allowNull: true,
+        field: 'cefr_level'
+    },
+    courseKind: {
+        type: DataTypes.TEXT,
+        allowNull: false,
+        defaultValue: 'core',
+        field: 'course_kind'
+    },
+    prerequisiteCourseId: {
+        type: DataTypes.INTEGER,
+        allowNull: true,
+        field: 'prerequisite_course_id'
+    },
     isPublic: {
         type: DataTypes.BOOLEAN,
         allowNull: false,

backend/models/community/vocab_listening_activity.js

@@ -0,0 +1,25 @@
+import { Model, DataTypes } from 'sequelize';
+import { sequelize } from '../../utils/sequelize.js';
+
+class VocabListeningActivity extends Model {}
+
+VocabListeningActivity.init({
+  id: { type: DataTypes.INTEGER, primaryKey: true, autoIncrement: true },
+  lessonId: { type: DataTypes.INTEGER, allowNull: false, field: 'lesson_id' },
+  audioUrl: { type: DataTypes.TEXT, allowNull: false, field: 'audio_url' },
+  transcript: { type: DataTypes.TEXT, allowNull: false },
+  translation: { type: DataTypes.TEXT, allowNull: true },
+  speakerProfile: { type: DataTypes.JSONB, allowNull: false, defaultValue: {} , field: 'speaker_profile' },
+  speed: { type: DataTypes.TEXT, allowNull: false, defaultValue: 'natural' },
+  questions: { type: DataTypes.JSONB, allowNull: false, defaultValue: [] },
+  createdAt: { type: DataTypes.DATE, allowNull: false, defaultValue: DataTypes.NOW, field: 'created_at' }
+}, {
+  sequelize,
+  modelName: 'VocabListeningActivity',
+  tableName: 'vocab_listening_activity',
+  schema: 'community',
+  timestamps: false,
+  underscored: true
+});
+
+export default VocabListeningActivity;

backend/models/index.js

@@ -158,6 +158,8 @@ import VocabGrammarExerciseType from './community/vocab_grammar_exercise_type.js
 import VocabGrammarExercise from './community/vocab_grammar_exercise.js';
 import VocabGrammarExerciseProgress from './community/vocab_grammar_exercise_progress.js';
 import VocabSrsItem from './community/vocab_srs_item.js';
+import VocabConversationSession from './community/vocab_conversation_session.js';
+import VocabListeningActivity from './community/vocab_listening_activity.js';
 import CalendarEvent from './community/calendar_event.js';
 
 const models = {
@@ -322,6 +324,8 @@ const models = {
   VocabGrammarExercise,
   VocabGrammarExerciseProgress,
   VocabSrsItem,
+  VocabConversationSession,
+  VocabListeningActivity,
   
   // Calendar
   CalendarEvent,