feat: 初始化短剧服务端（管理后台 API + 客户端 API）

Spring Boot 3.2 / MyBatis-Plus / PostgreSQL，7 个 Maven 模块；含认证鉴权、内容与媒资管理、操作日志，以及客户端 /app/** 接口。

reelshort-common/pom.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.reelshort</groupId>
+        <artifactId>reelshort</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>reelshort-common</artifactId>
+    <name>reelshort-common</name>
+    <description>通用模块：统一响应、分页、异常、工具</description>
+</project>

reelshort-common/src/main/java/com/reelshort/common/exception/ErrorCode.java

@@ -0,0 +1,39 @@
+package com.reelshort.common.exception;
+
+import lombok.Getter;
+
+/**
+ * 全局错误码，详见 docs/architecture-design.md 附录 A。
+ */
+@Getter
+public enum ErrorCode {
+
+    SUCCESS(0, "ok"),
+
+    BAD_REQUEST(400, "参数校验失败"),
+    UNAUTHORIZED(401, "未登录或登录已过期"),
+    FORBIDDEN(403, "无权限"),
+    NOT_FOUND(404, "资源不存在"),
+    TOO_MANY_REQUESTS(429, "请求过于频繁"),
+    INTERNAL_ERROR(500, "系统异常"),
+
+    LOGIN_FAILED(100000, "账号或密码错误"),
+    ACCOUNT_DISABLED(100001, "账号已停用"),
+    COIN_NOT_ENOUGH(100002, "金币余额不足"),
+    EPISODE_NOT_AVAILABLE(100003, "剧集未发布或不存在"),
+    EPISODE_UNLOCKED(100004, "剧集已解锁"),
+    ORDER_STATUS_INVALID(100005, "订单已支付或已关闭"),
+    VIP_EXPIRED(100006, "VIP 已过期"),
+
+    DATA_EXISTS(200001, "数据已存在"),
+    DATA_NOT_FOUND(200002, "数据不存在"),
+    OPERATION_NOT_ALLOWED(200003, "当前状态不允许该操作");
+
+    private final int code;
+    private final String message;
+
+    ErrorCode(int code, String message) {
+        this.code = code;
+        this.message = message;
+    }
+}

reelshort-common/src/main/java/com/reelshort/common/exception/ServiceException.java

@@ -0,0 +1,31 @@
+package com.reelshort.common.exception;
+
+import lombok.Getter;
+
+/**
+ * 业务异常：带业务错误码，由全局异常处理器转成统一响应。
+ */
+@Getter
+public class ServiceException extends RuntimeException {
+
+    private final int code;
+
+    public ServiceException(ErrorCode errorCode) {
+        super(errorCode.getMessage());
+        this.code = errorCode.getCode();
+    }
+
+    public ServiceException(ErrorCode errorCode, String message) {
+        super(message);
+        this.code = errorCode.getCode();
+    }
+
+    public ServiceException(String message) {
+        super(message);
+        this.code = ErrorCode.INTERNAL_ERROR.getCode();
+    }
+
+    public static ServiceException of(ErrorCode errorCode) {
+        return new ServiceException(errorCode);
+    }
+}

reelshort-common/src/main/java/com/reelshort/common/pojo/PageParam.java

@@ -0,0 +1,30 @@
+package com.reelshort.common.pojo;
+
+import lombok.Data;
+
+/**
+ * 分页请求参数，pageIndex 从 1 开始，与前端一致。
+ */
+@Data
+public class PageParam {
+
+    private static final int MAX_PAGE_SIZE = 200;
+
+    private Integer pageIndex = 1;
+    private Integer pageSize = 10;
+
+    public long getOffset() {
+        return (long) (getSafePageIndex() - 1) * getSafePageSize();
+    }
+
+    public int getSafePageIndex() {
+        return pageIndex == null || pageIndex < 1 ? 1 : pageIndex;
+    }
+
+    public int getSafePageSize() {
+        if (pageSize == null || pageSize < 1) {
+            return 10;
+        }
+        return Math.min(pageSize, MAX_PAGE_SIZE);
+    }
+}

reelshort-common/src/main/java/com/reelshort/common/pojo/PageResult.java

@@ -0,0 +1,21 @@
+package com.reelshort.common.pojo;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.util.List;
+
+/**
+ * 分页响应，字段名与前端表格组件（total / list）保持一致。
+ */
+@Getter
+@AllArgsConstructor
+public class PageResult<T> {
+
+    private final long total;
+    private final List<T> list;
+
+    public static <T> PageResult<T> empty() {
+        return new PageResult<>(0L, List.of());
+    }
+}

reelshort-common/src/main/java/com/reelshort/common/pojo/Result.java

@@ -0,0 +1,37 @@
+package com.reelshort.common.pojo;
+
+import com.reelshort.common.exception.ErrorCode;
+import lombok.Getter;
+
+/**
+ * 统一响应体，与前端 axios 拦截器约定一致：{ code, message, data }。
+ */
+@Getter
+public class Result<T> {
+
+    private final int code;
+    private final String message;
+    private final T data;
+
+    private Result(int code, String message, T data) {
+        this.code = code;
+        this.message = message;
+        this.data = data;
+    }
+
+    public static Result<Void> ok() {
+        return new Result<>(ErrorCode.SUCCESS.getCode(), ErrorCode.SUCCESS.getMessage(), null);
+    }
+
+    public static <T> Result<T> ok(T data) {
+        return new Result<>(ErrorCode.SUCCESS.getCode(), ErrorCode.SUCCESS.getMessage(), data);
+    }
+
+    public static <T> Result<T> error(ErrorCode errorCode) {
+        return new Result<>(errorCode.getCode(), errorCode.getMessage(), null);
+    }
+
+    public static <T> Result<T> error(int code, String message) {
+        return new Result<>(code, message, null);
+    }
+}