feat(client): 完成 P3 业务页联动闭环（D6/D8/D10/D11）

- 待办：列表/详情 + approve/reject/return/transfer（D6）
- 报销：列表/详情 + create/submit/withdraw/pay（D8）
- 票据：列表/上传/OCR轮询/绑定/预览（D10）
- 统一：Api types + 错误映射 + react-query缓存失效（D11）

client/src/api/workflow.ts

@@ -0,0 +1,163 @@
+import { apiRequestData } from "./http";
+
+export type WorkflowTaskSummary = {
+  id: string;
+  instanceId: string;
+  stepId: string;
+  stepName: string;
+  assigneeId: string | null;
+  assigneeRole: string | null;
+  status: "pending" | "completed" | "rejected" | "cancelled" | "skipped";
+  outcome: string | null;
+  createdAt: string;
+  completedAt: string | null;
+  workflowInstance: {
+    entityType: string;
+    entityId: string;
+    currentStatus: string;
+  } | null;
+};
+
+export type WorkflowTaskListResponse = {
+  page: number;
+  pageSize: number;
+  total: number;
+  items: WorkflowTaskSummary[];
+};
+
+export type WorkflowHistoryItem = {
+  id: string;
+  taskId: string | null;
+  actorId: string;
+  actorName: string;
+  actorEmployeeNo: string;
+  action: string;
+  comment: string | null;
+  payload: Record<string, unknown> | null;
+  createdAt: string | null;
+};
+
+export type WorkflowTaskDetail = {
+  task: {
+    id: string;
+    instanceId: string;
+    stepId: string;
+    stepName: string;
+    assigneeId: string | null;
+    assigneeRole: string | null;
+    status: string;
+    outcome: string | null;
+    comment: string | null;
+    createdAt: string | null;
+    completedAt: string | null;
+  };
+  workflowInstance: {
+    id: string;
+    currentStatus: string;
+    currentStepId: string;
+    startedAt: string | null;
+    completedAt: string | null;
+  } | null;
+  reimbursement: {
+    id: string;
+    formNumber: string | null;
+    status: string;
+    reimbursementDate: string | null;
+    totalAmount: string | null;
+    description: string | null;
+    owner: {
+      id: string;
+      employeeNo: string;
+      name: string;
+    } | null;
+    submitter: {
+      id: string;
+      employeeNo: string;
+      name: string;
+    } | null;
+  } | null;
+  allowedActions: Array<"approve" | "reject" | "return" | "transfer">;
+  history: WorkflowHistoryItem[];
+};
+
+export type WorkflowApprover = {
+  id: string;
+  employeeNo: string;
+  name: string;
+  email: string;
+  roleCodes: string[];
+};
+
+export type WorkflowApproverListResponse = {
+  page: number;
+  pageSize: number;
+  total: number;
+  items: WorkflowApprover[];
+};
+
+export type WorkflowTaskListQuery = {
+  status?: "pending" | "completed" | "rejected" | "cancelled" | "skipped";
+  page?: number;
+  pageSize?: number;
+};
+
+export type WorkflowApproverQuery = {
+  keyword?: string;
+  page?: number;
+  pageSize?: number;
+};
+
+function toQueryString(query: Record<string, string | number | undefined>) {
+  const params = new URLSearchParams();
+  for (const [key, value] of Object.entries(query)) {
+    if (value == null || value === "") {
+      continue;
+    }
+    params.set(key, String(value));
+  }
+
+  const encoded = params.toString();
+  return encoded ? `?${encoded}` : "";
+}
+
+export async function fetchWorkflowTasks(query: WorkflowTaskListQuery) {
+  return apiRequestData<WorkflowTaskListResponse>(`/api/workflow/tasks${toQueryString(query)}`);
+}
+
+export async function fetchWorkflowTaskDetail(taskId: string) {
+  return apiRequestData<WorkflowTaskDetail>(`/api/workflow/tasks/${taskId}`);
+}
+
+export async function fetchWorkflowApprovers(query: WorkflowApproverQuery = {}) {
+  return apiRequestData<WorkflowApproverListResponse>(
+    `/api/workflow/approvers${toQueryString(query as Record<string, string | number | undefined>)}`,
+  );
+}
+
+export async function approveWorkflowTask(taskId: string) {
+  return apiRequestData<Record<string, unknown>>(`/api/workflow/tasks/${taskId}/approve`, {
+    method: "POST",
+    body: JSON.stringify({}),
+  });
+}
+
+export async function rejectWorkflowTask(taskId: string, comment: string) {
+  return apiRequestData<Record<string, unknown>>(`/api/workflow/tasks/${taskId}/reject`, {
+    method: "POST",
+    body: JSON.stringify({ comment }),
+  });
+}
+
+export async function returnWorkflowTask(taskId: string, comment: string) {
+  return apiRequestData<Record<string, unknown>>(`/api/workflow/tasks/${taskId}/return`, {
+    method: "POST",
+    body: JSON.stringify({ comment }),
+  });
+}
+
+export async function transferWorkflowTask(taskId: string, toApproverId: string, reason: string) {
+  return apiRequestData<Record<string, unknown>>(`/api/workflow/tasks/${taskId}/transfer`, {
+    method: "POST",
+    body: JSON.stringify({ toApproverId, reason }),
+  });
+}