feat: 修復 AI 生成同義詞完整保存功能

- 添加 Synonyms 屬性到 Flashcard 實體模型並配置 DbContext
- 執行 FixSynonymsColumn migration 在資料庫中添加 synonyms 欄位
- 更新前後端 CreateFlashcardRequest DTO 支援同義詞傳輸
- 修復前端 generate page 包含 AI 生成的同義詞資料
- 添加前端安全 JSON 解析，正確顯示同義詞標籤
- 修復完整資料流程：AI 分析 → 前端處理 → API 傳輸 → 資料庫儲存

現在 AI 生成的同義詞不再被浪費，完整保存並在詞卡詳細頁面顯示。

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/DramaLing.Api/Controllers/FlashcardsController.cs

@@ -62,6 +62,7 @@ public class FlashcardsController : BaseController
                         f.Example,
                         f.ExampleTranslation,
                         f.IsFavorite,
+                        f.Synonyms,
                         DifficultyLevelNumeric = f.DifficultyLevelNumeric,
                         CEFR = CEFRHelper.ToString(f.DifficultyLevelNumeric),
                         f.CreatedAt,
@@ -117,6 +118,7 @@ public class FlashcardsController : BaseController
                 Pronunciation = request.Pronunciation,
                 Example = request.Example,
                 ExampleTranslation = request.ExampleTranslation,
+                Synonyms = request.Synonyms, // 儲存 AI 生成的同義詞
                 DifficultyLevelNumeric = CEFRHelper.ToNumeric(request.CEFR ?? "A0"),
                 CreatedAt = DateTime.UtcNow,
                 UpdatedAt = DateTime.UtcNow
@@ -168,6 +170,7 @@ public class FlashcardsController : BaseController
                 flashcard.Example,
                 flashcard.ExampleTranslation,
                 flashcard.IsFavorite,
+                flashcard.Synonyms,
                 DifficultyLevelNumeric = flashcard.DifficultyLevelNumeric,
                 CEFR = CEFRHelper.ToString(flashcard.DifficultyLevelNumeric),
                 flashcard.CreatedAt,
@@ -402,5 +405,6 @@ public class CreateFlashcardRequest
     public string Pronunciation { get; set; } = string.Empty;
     public string Example { get; set; } = string.Empty;
     public string? ExampleTranslation { get; set; }
+    public string? Synonyms { get; set; } // AI 生成的同義詞 (JSON 字串)
     public string? CEFR { get; set; } = string.Empty;
 }

backend/DramaLing.Api/Data/DramaLingDbContext.cs

@@ -129,6 +129,7 @@ public class DramaLingDbContext : DbContext
         flashcardEntity.Property(f => f.Pronunciation).HasColumnName("pronunciation");
         flashcardEntity.Property(f => f.Example).HasColumnName("example");
         flashcardEntity.Property(f => f.ExampleTranslation).HasColumnName("example_translation");
+        flashcardEntity.Property(f => f.Synonyms).HasColumnName("synonyms");
         // 已刪除的復習相關屬性配置
         // EasinessFactor, IntervalDays, NextReviewDate, MasteryLevel,
         // TimesReviewed, TimesCorrect, LastReviewedAt 已移除

backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DramaLing.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class FixSynonymsColumn : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "synonyms",
+                table: "flashcards",
+                type: "TEXT",
+                maxLength: 2000,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "synonyms",
+                table: "flashcards");
+        }
+    }
+}

backend/DramaLing.Api/Migrations/DramaLingDbContextModelSnapshot.cs

@@ -348,6 +348,11 @@ namespace DramaLing.Api.Migrations
                         .HasColumnType("TEXT")
                         .HasColumnName("pronunciation");
 
+                    b.Property<string>("Synonyms")
+                        .HasMaxLength(2000)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("synonyms");
+
                     b.Property<string>("Translation")
                         .IsRequired()
                         .HasColumnType("TEXT")

backend/DramaLing.Api/Models/Entities/Flashcard.cs

@@ -34,6 +34,9 @@ public class Flashcard
 
     public string? ExampleTranslation { get; set; }
 
+    [MaxLength(2000)]
+    public string? Synonyms { get; set; }
+
     // 基本狀態
     public bool IsFavorite { get; set; } = false;
 

frontend/app/generate/page.tsx

@@ -202,6 +202,7 @@ function GenerateContent() {
         partOfSpeech: analysis.partOfSpeech || analysis.PartOfSpeech || 'noun',
         example: analysis.example || `Example sentence with ${word}.`, // 使用分析結果的例句
         exampleTranslation: analysis.exampleTranslation,
+        synonyms: analysis.synonyms ? JSON.stringify(analysis.synonyms) : undefined, // 轉換為 JSON 字串
         cefr: cefrValue
       }
 

frontend/components/flashcards/FlashcardContentBlocks.tsx

@@ -22,6 +22,23 @@ export const FlashcardContentBlocks: React.FC<FlashcardContentBlocksProps> = ({
   generationProgress,
   onGenerateImage
 }) => {
+  // 安全解析同義詞 JSON 字串
+  const parseSynonyms = (synonymsData: any): string[] => {
+    if (!synonymsData) return []
+    if (Array.isArray(synonymsData)) return synonymsData
+    if (typeof synonymsData === 'string') {
+      try {
+        const parsed = JSON.parse(synonymsData)
+        return Array.isArray(parsed) ? parsed : []
+      } catch {
+        return []
+      }
+    }
+    return []
+  }
+
+  const synonymsList = parseSynonyms((flashcard as any).synonyms)
+
   return (
     <div className="p-6 space-y-6">
       {/* 翻譯區塊 */}
@@ -173,11 +190,11 @@ export const FlashcardContentBlocks: React.FC<FlashcardContentBlocksProps> = ({
       </div>
 
       {/* 同義詞區塊 */}
-      {(flashcard as any).synonyms && (flashcard as any).synonyms.length > 0 && (
+      {synonymsList.length > 0 && (
         <div className="bg-purple-50 rounded-lg p-4 border border-purple-200">
           <h3 className="font-semibold text-purple-900 mb-3 text-left">同義詞</h3>
           <div className="flex flex-wrap gap-2">
-            {(flashcard as any).synonyms.map((synonym: string, index: number) => (
+            {synonymsList.map((synonym: string, index: number) => (
               <span
                 key={index}
                 className="bg-white text-purple-700 px-3 py-1 rounded-full text-sm border border-purple-200 font-medium"

frontend/components/flashcards/SearchControls.tsx

@@ -29,7 +29,6 @@ export const SearchControls: React.FC<SearchControlsProps> = ({
               className="text-sm border border-gray-300 rounded-md px-3 py-1 focus:ring-2 focus:ring-primary focus:border-primary"
             >
               <option value="createdAt">創建時間</option>
-              <option value="masteryLevel">掌握程度</option>
               <option value="word">字母順序</option>
               <option value="cefr">CEFR等級</option>
               <option value="timesReviewed">複習次數</option>

frontend/lib/services/flashcards.ts

@@ -43,6 +43,7 @@ export interface CreateFlashcardRequest {
   partOfSpeech: string;
   example: string;
   exampleTranslation?: string;
+  synonyms?: string; // AI 生成的同義詞 (JSON 字串格式)
   cefr?: string; // A1, A2, B1, B2, C1, C2
 }