feat: 添加 Android 会议相关 DTO 和积分处理 DTO

- 新增 `AndroidMeetingListItemVO` 和 `AndroidMeetingCreateResponse` 用于 Android 会议列表和创建响应
- 新增 `MeetingPointsTransferRequest` 用于公共积分分配给个人请求
- 新增 `MeetingPointsChargeItemVO` 用于会议积分扣费明细视图

backend/src/main/java/com/imeeting/dto/android/AndroidMeetingCreateResponse.java

@@ -0,0 +1,15 @@
+package com.imeeting.dto.android;
+
+import com.imeeting.dto.biz.MeetingVO;
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+@Data
+@EqualsAndHashCode(callSuper = true)
+@Schema(description = "Android 创建会议返回对象")
+public class AndroidMeetingCreateResponse extends MeetingVO {
+
+    @Schema(description = "H5 会议预览地址")
+    private String previewUrl;
+}

backend/src/main/java/com/imeeting/dto/android/AndroidMeetingListItemVO.java

@@ -0,0 +1,18 @@
+package com.imeeting.dto.android;
+
+import com.imeeting.dto.biz.MeetingVO;
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+@Data
+@EqualsAndHashCode(callSuper = true)
+@Schema(description = "Android 会议列表项")
+public class AndroidMeetingListItemVO extends MeetingVO {
+
+    @Schema(description = "H5 会议预览地址")
+    private String previewUrl;
+
+    @Schema(description = "会议日期相对当前日期的天数偏移量，今天为 0，未来为正，过去为负")
+    private Long dayOffset;
+}

backend/src/main/java/com/imeeting/dto/biz/MeetingPointsChargeItemVO.java

@@ -0,0 +1,32 @@
+package com.imeeting.dto.biz;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Data;
+
+@Data
+@Schema(description = "会议积分扣费明细视图")
+public class MeetingPointsChargeItemVO {
+    @Schema(description = "明细ID，这里复用 ledger ID")
+    private Long id;
+
+    @Schema(description = "扣费阶段：ASR / LLM")
+    private String chargeStage;
+
+    @Schema(description = "实际扣费账户类型：PUBLIC / PERSONAL")
+    private String accountType;
+
+    @Schema(description = "实际扣费账户用户ID")
+    private Long accountUserId;
+
+    @Schema(description = "在本次扣费中的顺序")
+    private Integer priorityOrder;
+
+    @Schema(description = "本条实际扣费积分")
+    private Long chargedPoints;
+
+    @Schema(description = "扣费前余额")
+    private Long balanceBefore;
+
+    @Schema(description = "扣费后余额")
+    private Long balanceAfter;
+}

backend/src/main/java/com/imeeting/dto/biz/MeetingPointsTransferRequest.java

@@ -0,0 +1,17 @@
+package com.imeeting.dto.biz;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Data;
+
+@Data
+@Schema(description = "公共积分分配给个人请求")
+public class MeetingPointsTransferRequest {
+    @Schema(description = "目标用户ID")
+    private Long targetUserId;
+
+    @Schema(description = "分配积分数量")
+    private Long points;
+
+    @Schema(description = "备注")
+    private String remark;
+}