refactor: 完成项目整体目录重构与路径别名配置

1.  重构项目文件结构，统一文件存放位置与命名规则
2.  配置tsconfig路径别名，替换原有相对路径导入
3.  迁移drama-status枚举到dramas.types统一管理
4.  新增全局配置文件与工具类，补充完整注释与文档
5.  修复所有导入路径与依赖引用问题

config/app.config.ts

@@ -0,0 +1,59 @@
+/**
+ * App config.
+ * @file 应用运行配置
+ * @module config/app.config
+ * @author zhxiao1124
+ */
+
+// 注意：本文件不主动加载 .env，环境变量由 src/main.ts 顶部的 `import "dotenv/config"` 注入。
+// e2e 测试不加载 .env，DB_CONFIG.host 为空时应用自动退回内存模式（见 src/app/app.module.ts 的门控）。
+
+const numberEnv = (key: string, fallback: number) => {
+    const value = Number(process.env[key]);
+    return Number.isFinite(value) ? value : fallback;
+};
+
+const boolEnv = (key: string, fallback: boolean) => {
+    const value = process.env[key];
+    if (value === undefined) return fallback;
+    return value === "true" || value === "1";
+};
+
+export const APP_CONFIG = {
+    APP_NAME: "cth-tk-backend",
+    PORT: numberEnv("PORT", 3000),
+};
+
+export const OPTIONS_CONFIG = {
+    cors: {
+        origin: process.env.CORS_ORIGIN?.split(","),
+        credentials: true,
+    },
+};
+
+export const DB_CONFIG = {
+    type: "mysql" as const,
+    host: process.env.DB_HOST,
+    port: numberEnv("DB_PORT", 3306),
+    username: process.env.DB_USERNAME ?? "root",
+    password: process.env.DB_PASSWORD ?? "",
+    database: process.env.DB_DATABASE ?? "cth_tk",
+    synchronize: boolEnv("DB_SYNCHRONIZE", false),
+};
+
+export const AUTH_CONFIG = {
+    jwtTokenSecret: process.env.JWT_SECRET ?? "development-secret",
+    expiresIn: "30d" as const,
+};
+
+export const ADMIN_AUTH_CONFIG = {
+    jwtTokenSecret: process.env.ADMIN_JWT_SECRET ?? process.env.JWT_SECRET ?? "development-secret",
+    expiresIn: "12h" as const,
+    username: process.env.ADMIN_USERNAME ?? "admin",
+    password: process.env.ADMIN_PASSWORD ?? "admin123",
+    email: process.env.ADMIN_EMAIL ?? "admin@example.com",
+};
+
+export const BYTEPLUS_CONFIG = {
+    bucket: process.env.BYTEPLUS_BUCKET ?? "mock-short-drama",
+};