feat: 啟動詞卡管理功能開發，完成後端 API 驗證

🚀 第一階段開發成果：
- 成功驗證 CardSets 和 Flashcards API 端點
- 修復 JSON 循環引用問題（ReferenceHandler.IgnoreCycles）
- 建立基礎測試資料：商務英語詞卡集合
- 創建範例詞卡：negotiate, meeting, presentation
- 驗證真實資料庫 CRUD 操作

🔧 技術改進：
- 配置 JSON 序列化選項防止循環引用
- 完整的錯誤日誌系統發揮作用
- 資料庫關聯正常運作

📋 下一步：前端整合，讓用戶看到真實資料

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

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

backend/DramaLing.Api/Program.cs

@@ -9,7 +9,12 @@ using System.Text;
 var builder = WebApplication.CreateBuilder(args);
 
 // Add services to the container.
-builder.Services.AddControllers();
+builder.Services.AddControllers()
+    .AddJsonOptions(options =>
+    {
+        options.JsonSerializerOptions.ReferenceHandler = System.Text.Json.Serialization.ReferenceHandler.IgnoreCycles;
+        options.JsonSerializerOptions.WriteIndented = true;
+    });
 
 // Entity Framework - 使用 SQLite 進行測試
 var useInMemoryDb = Environment.GetEnvironmentVariable("USE_INMEMORY_DB") == "true";

frontend/.next/app-build-manifest.json

@@ -31,10 +31,10 @@
       "static/chunks/main-app.js",
       "static/chunks/app/login/page.js"
     ],
-    "/_not-found/page": [
+    "/flashcards/page": [
       "static/chunks/webpack.js",
       "static/chunks/main-app.js",
-      "static/chunks/app/_not-found/page.js"
+      "static/chunks/app/flashcards/page.js"
     ]
   }
 }

frontend/.next/server/app-paths-manifest.json

@@ -1,6 +1,7 @@
 {
-  "/_not-found/page": "app/_not-found/page.js",
+  "/register/page": "app/register/page.js",
-  "/dashboard/page": "app/dashboard/page.js",
   "/login/page": "app/login/page.js",
-  "/register/page": "app/register/page.js"
+  "/learn/page": "app/learn/page.js",
+  "/dashboard/page": "app/dashboard/page.js",
+  "/flashcards/page": "app/flashcards/page.js"
 }

frontend/.next/static/webpack/98616de372651724.webpack.hot-update.json

@@ -0,0 +1 @@
+{"c":["webpack"],"r":["app/_not-found/page"],"m":["(app-pages-browser)/./node_modules/next/dist/build/webpack/loaders/next-client-pages-loader.js?absolutePagePath=%2FUsers%2Fjettcheng1018%2Fcode%2Fdramaling-vocab-learning%2Ffrontend%2Fnode_modules%2Fnext%2Fdist%2Fclient%2Fcomponents%2Fbuiltin%2Fglobal-not-found.js&page=%2F_not-found%2Fpage!","(app-pages-browser)/./node_modules/next/dist/client/components/builtin/global-not-found.js","(app-pages-browser)/./node_modules/next/dist/client/components/http-access-fallback/error-fallback.js","(app-pages-browser)/./node_modules/next/dist/client/components/styles/access-error-styles.js"]}

frontend/.next/static/webpack/webpack.98616de372651724.hot-update.js

@@ -0,0 +1,12 @@
+"use strict";
+self["webpackHotUpdate_N_E"]("webpack",{},
+/******/ function(__webpack_require__) { // webpackRuntimeModules
+/******/ /* webpack/runtime/getFullHash */
+/******/ (() => {
+/******/ 	__webpack_require__.h = () => ("1ba7acc777cf829e")
+/******/ })();
+/******/ 
+/******/ }
+)
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
+;

frontend/.next/types/app/flashcards/page.ts

@@ -0,0 +1,84 @@
+// File: /Users/jettcheng1018/code/dramaling-vocab-learning/frontend/app/flashcards/page.tsx
+import * as entry from '../../../../app/flashcards/page.js'
+import type { ResolvingMetadata, ResolvingViewport } from 'next/dist/lib/metadata/types/metadata-interface.js'
+
+type TEntry = typeof import('../../../../app/flashcards/page.js')
+
+type SegmentParams<T extends Object = any> = T extends Record<string, any>
+  ? { [K in keyof T]: T[K] extends string ? string | string[] | undefined : never }
+  : T
+
+// Check that the entry is a valid entry
+checkFields<Diff<{
+  default: Function
+  config?: {}
+  generateStaticParams?: Function
+  revalidate?: RevalidateRange<TEntry> | false
+  dynamic?: 'auto' | 'force-dynamic' | 'error' | 'force-static'
+  dynamicParams?: boolean
+  fetchCache?: 'auto' | 'force-no-store' | 'only-no-store' | 'default-no-store' | 'default-cache' | 'only-cache' | 'force-cache'
+  preferredRegion?: 'auto' | 'global' | 'home' | string | string[]
+  runtime?: 'nodejs' | 'experimental-edge' | 'edge'
+  maxDuration?: number
+  
+  metadata?: any
+  generateMetadata?: Function
+  viewport?: any
+  generateViewport?: Function
+  experimental_ppr?: boolean
+  
+}, TEntry, ''>>()
+
+
+// Check the prop type of the entry function
+checkFields<Diff<PageProps, FirstArg<TEntry['default']>, 'default'>>()
+
+// Check the arguments and return type of the generateMetadata function
+if ('generateMetadata' in entry) {
+  checkFields<Diff<PageProps, FirstArg<MaybeField<TEntry, 'generateMetadata'>>, 'generateMetadata'>>()
+  checkFields<Diff<ResolvingMetadata, SecondArg<MaybeField<TEntry, 'generateMetadata'>>, 'generateMetadata'>>()
+}
+
+// Check the arguments and return type of the generateViewport function
+if ('generateViewport' in entry) {
+  checkFields<Diff<PageProps, FirstArg<MaybeField<TEntry, 'generateViewport'>>, 'generateViewport'>>()
+  checkFields<Diff<ResolvingViewport, SecondArg<MaybeField<TEntry, 'generateViewport'>>, 'generateViewport'>>()
+}
+
+// Check the arguments and return type of the generateStaticParams function
+if ('generateStaticParams' in entry) {
+  checkFields<Diff<{ params: SegmentParams }, FirstArg<MaybeField<TEntry, 'generateStaticParams'>>, 'generateStaticParams'>>()
+  checkFields<Diff<{ __tag__: 'generateStaticParams', __return_type__: any[] | Promise<any[]> }, { __tag__: 'generateStaticParams', __return_type__: ReturnType<MaybeField<TEntry, 'generateStaticParams'>> }>>()
+}
+
+export interface PageProps {
+  params?: Promise<SegmentParams>
+  searchParams?: Promise<any>
+}
+export interface LayoutProps {
+  children?: React.ReactNode
+
+  params?: Promise<SegmentParams>
+}
+
+// =============
+// Utility types
+type RevalidateRange<T> = T extends { revalidate: any } ? NonNegative<T['revalidate']> : never
+
+// If T is unknown or any, it will be an empty {} type. Otherwise, it will be the same as Omit<T, keyof Base>.
+type OmitWithTag<T, K extends keyof any, _M> = Omit<T, K>
+type Diff<Base, T extends Base, Message extends string = ''> = 0 extends (1 & T) ? {} : OmitWithTag<T, keyof Base, Message>
+
+type FirstArg<T extends Function> = T extends (...args: [infer T, any]) => any ? unknown extends T ? any : T : never
+type SecondArg<T extends Function> = T extends (...args: [any, infer T]) => any ? unknown extends T ? any : T : never
+type MaybeField<T, K extends string> = T extends { [k in K]: infer G } ? G extends Function ? G : never : never
+
+
+
+function checkFields<_ extends { [k in keyof any]: never }>() {}
+
+// https://github.com/sindresorhus/type-fest
+type Numeric = number | bigint
+type Zero = 0 | 0n
+type Negative<T extends Numeric> = T extends Zero ? never : `${T}` extends `-${string}` ? T : never
+type NonNegative<T extends Numeric> = T extends Zero ? T : Negative<T> extends never ? T : '__invalid_negative_number__'