feat: 提交流程中心后端代码

Spring Boot 流程引擎服务：流程定义/实例/任务、审批人解析、
回调分发、oapi 接口及单元测试。
保留远程 .gitea/workflows/build.yml 与 docker/Dockerfile，
新增 .gitignore 排除 target/ 构建产物。

src/main/java/com/yunhai/flowcenter/model/FlowModels.java

@@ -0,0 +1,115 @@
+package com.yunhai.flowcenter.model;
+
+import lombok.Data;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * 用户面/管理面 VO（/api/flow/**）。
+ */
+public final class FlowModels {
+
+    private FlowModels() {
+    }
+
+    /** 我的办件列表行 */
+    @Data
+    public static class InstanceItem {
+        private Long instanceId;
+        private String bizType;
+        private String bizId;
+        private String bizTitle;
+        private Integer status;
+        private String currentNodes;
+        private String submitterName;
+        private String submitTime;
+        private String finishTime;
+        private String defName;
+        private Integer defVersion;
+    }
+
+    /** 待办/已办列表行 */
+    @Data
+    public static class TaskItem {
+        private Long taskId;
+        private Long instanceId;
+        private String bizTitle;
+        private String bizType;
+        private String bizId;
+        private Integer instanceStatus;
+        private String nodeId;
+        private String nodeName;
+        private String assigneeName;
+        private Integer status;
+        private String opinion;
+        private String arriveTime;
+        private String handleTime;
+        private String deadline;
+        private Integer urgeCount;
+    }
+
+    /** 办件详情（办理页/详情页数据源） */
+    @Data
+    public static class InstanceDetail {
+        private Long instanceId;
+        private Long schId;
+        private String defCode;
+        private Integer defVersion;
+        private String bizType;
+        private String bizId;
+        private String bizTitle;
+        private String bizUrl;
+        /** 业务摘要 JSON（办理页区块渲染；无富文本正文——概览 §十边界） */
+        private String bizSnapshot;
+        private String formDataJson;
+        private Integer status;
+        private String currentNodes;
+        private Integer submitterId;
+        private String submitterName;
+        private String submitTime;
+        private String finishTime;
+        private Integer version;
+        private String nodeSummary;
+        private List<Map<String, Object>> trace;
+        private List<Map<String, Object>> branches;
+        /** 当前用户可否办理（存在本人的待办任务） */
+        private boolean myPendingTask;
+        private List<Long> myPendingTaskIds;
+    }
+
+    /** 流程示意图出参（用户面 /diagram 与管理面 /admin/def/diagram 共用，方案 §3.1） */
+    @Data
+    public static class DiagramVo {
+        private String flowGuid;
+        private Long defId;
+        private Long instanceId;
+        private String name;
+        private Integer version;
+        private Integer status;
+        /** 实际出图口径：dept｜user｜auto（后端归一化后回显） */
+        private String mode;
+        private List<NodeVo> nodes;
+        private List<EdgeVo> edges;
+    }
+
+    /** 示意图节点（label/subLabel 已按视图解析好，前端只画不解析） */
+    @Data
+    public static class NodeVo {
+        private String id;
+        private String type;
+        private String label;
+        private String subLabel;
+        private String deptKey;
+        private String assigneeType;
+        private String countersign;
+        private Integer deadlineHours;
+    }
+
+    /** 示意图连边 */
+    @Data
+    public static class EdgeVo {
+        private String from;
+        private String to;
+    }
+}

src/main/java/com/yunhai/flowcenter/model/OapiModels.java

@@ -0,0 +1,84 @@
+package com.yunhai.flowcenter.model;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import lombok.Data;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * /oapi/flow/** 契约模型（出入参字段与 svc-hall FlowCenterClient 逐字对齐，
+ * 契约锚点：《流程中心M1开工说明.md》§5——两侧已编码，改动须双向同步）。
+ */
+public final class OapiModels {
+
+    private OapiModels() {
+    }
+
+    /** 流程摘要（list 元素 / {flowGuid} 详情） */
+    @Data
+    @JsonIgnoreProperties(ignoreUnknown = true)
+    public static class FlowSummaryVo {
+        private String flowGuid;
+        private String name;
+        private Integer version;
+        private String nodeSummary;
+    }
+
+    /** 代发起请求体（POST /oapi/flow/apply；formData 为 JSON 对象透传） */
+    @Data
+    @JsonIgnoreProperties(ignoreUnknown = true)
+    public static class ApplyBody {
+        private String flowGuid;
+        private String bizType;
+        private String bizId;
+        private String bizTitle;
+        private String bizUrl;
+        /** 业务摘要 JSON 快照（字符串或对象均可，统一落字符串） */
+        private Object bizSnapshot;
+        private Integer submitterId;
+        private String submitterName;
+        /** 表单数据对象（业务方编辑页产出，无表单模式不传） */
+        private Map<String, Object> formData;
+    }
+
+    /** 代发起响应（biz uk 幂等：重复代发起 HTTP 200 + duplicated:true 返回既有办件） */
+    @Data
+    public static class ApplyResultVo {
+        private Long instanceId;
+        private boolean duplicated;
+    }
+
+    /** 按业务键查办件响应（对账兜底；traceJson 含 assigneeId 轨迹供办理人放行判定） */
+    @Data
+    public static class InstanceVo {
+        private Long instanceId;
+        private Integer status;
+        private Integer version;
+        private String nodeSummary;
+        private String traceJson;
+        private List<Integer> assigneeIds;
+        private String currentNodes;
+        private String bizTitle;
+        private Integer submitterId;
+        private String submitterName;
+        private String submitTime;
+        private String finishTime;
+    }
+
+    /** 回调注册请求体（POST /oapi/flow/callback/reg） */
+    @Data
+    @JsonIgnoreProperties(ignoreUnknown = true)
+    public static class CallbackRegBody {
+        private String flowGuid;
+        private String callbackUrl;
+        /** 订阅事件逗号分隔，空=全部 */
+        private String eventTypes;
+    }
+
+    /** 回调注册响应（secret 注册时生成下发） */
+    @Data
+    public static class CallbackRegResultVo {
+        private String secret;
+    }
+}