feat(web): wire ProcessViewer and delegate UI into workflow pages

- InstanceMonitor: add '流程图' button that opens ProcessViewer modal
  with active node highlighting, loading flow definition via API
- PendingTasks: add '委派' button with delegate modal (UUID input),
  wired to the existing delegateTask API function
- Both ProcessViewer component and delegateTask API were previously
  dead code (never imported/called)

apps/web/src/pages/workflow/InstanceMonitor.tsx

@@ -6,6 +6,8 @@ import {
   terminateInstance,
   type ProcessInstanceInfo,
 } from '../../api/workflowInstances';
+import { getProcessDefinition, type NodeDef, type EdgeDef } from '../../api/workflowDefinitions';
+import ProcessViewer from './ProcessViewer';
 
 const statusColors: Record<string, string> = {
   running: 'processing',
@@ -20,6 +22,13 @@ export default function InstanceMonitor() {
   const [page, setPage] = useState(1);
   const [loading, setLoading] = useState(false);
 
+  // ProcessViewer state
+  const [viewerOpen, setViewerOpen] = useState(false);
+  const [viewerNodes, setViewerNodes] = useState<NodeDef[]>([]);
+  const [viewerEdges, setViewerEdges] = useState<EdgeDef[]>([]);
+  const [activeNodeIds, setActiveNodeIds] = useState<string[]>([]);
+  const [viewerLoading, setViewerLoading] = useState(false);
+
   const fetchData = useCallback(async () => {
     setLoading(true);
     try {
@@ -33,6 +42,22 @@ export default function InstanceMonitor() {
 
   useEffect(() => { fetchData(); }, [fetchData]);
 
+  const handleViewFlow = async (record: ProcessInstanceInfo) => {
+    setViewerLoading(true);
+    setViewerOpen(true);
+    try {
+      const def = await getProcessDefinition(record.definition_id);
+      setViewerNodes(def.nodes);
+      setViewerEdges(def.edges);
+      setActiveNodeIds(record.active_tokens.map((t) => t.node_id));
+    } catch {
+      message.error('加载流程图失败');
+      setViewerOpen(false);
+    } finally {
+      setViewerLoading(false);
+    }
+  };
+
   const handleTerminate = async (id: string) => {
     Modal.confirm({
       title: '确认终止',
@@ -66,16 +91,22 @@ export default function InstanceMonitor() {
       render: (v: string) => new Date(v).toLocaleString(),
     },
     {
-      title: '操作', key: 'action', width: 100,
+      title: '操作', key: 'action', width: 150,
       render: (_, record) => (
-        record.status === 'running' ? (
+        <>
+          <Button size="small" onClick={() => handleViewFlow(record)} style={{ marginRight: 8 }}>
+            流程图
+          </Button>
+          {record.status === 'running' && (
             <Button size="small" danger onClick={() => handleTerminate(record.id)}>终止</Button>
-        ) : null
+          )}
+        </>
       ),
     },
   ];
 
   return (
+    <>
       <Table
         rowKey="id"
         columns={columns}
@@ -83,5 +114,16 @@ export default function InstanceMonitor() {
         loading={loading}
         pagination={{ current: page, total, pageSize: 20, onChange: setPage }}
       />
+      <Modal
+        title="流程图查看"
+        open={viewerOpen}
+        onCancel={() => setViewerOpen(false)}
+        footer={null}
+        width={720}
+        loading={viewerLoading}
+      >
+        <ProcessViewer nodes={viewerNodes} edges={viewerEdges} activeNodeIds={activeNodeIds} />
+      </Modal>
+    </>
   );
 }

apps/web/src/pages/workflow/PendingTasks.tsx

@@ -1,9 +1,10 @@
 import { useCallback, useEffect, useState } from 'react';
-import { Button, message, Modal, Space, Table, Tag } from 'antd';
+import { Button, Input, message, Modal, Space, Table, Tag } from 'antd';
 import type { ColumnsType } from 'antd/es/table';
 import {
   listPendingTasks,
   completeTask,
+  delegateTask,
   type TaskInfo,
 } from '../../api/workflowTasks';
 
@@ -18,6 +19,8 @@ export default function PendingTasks() {
   const [loading, setLoading] = useState(false);
   const [completeModal, setCompleteModal] = useState<TaskInfo | null>(null);
   const [outcome, setOutcome] = useState('approved');
+  const [delegateModal, setDelegateModal] = useState<TaskInfo | null>(null);
+  const [delegateTo, setDelegateTo] = useState('');
 
   const fetchData = useCallback(async () => {
     setLoading(true);
@@ -44,6 +47,22 @@ export default function PendingTasks() {
     }
   };
 
+  const handleDelegate = async () => {
+    if (!delegateModal || !delegateTo.trim()) {
+      message.warning('请输入委派目标用户 ID');
+      return;
+    }
+    try {
+      await delegateTask(delegateModal.id, { delegate_to: delegateTo.trim() });
+      message.success('委派成功');
+      setDelegateModal(null);
+      setDelegateTo('');
+      fetchData();
+    } catch {
+      message.error('委派失败');
+    }
+  };
+
   const columns: ColumnsType<TaskInfo> = [
     { title: '任务名称', dataIndex: 'node_name', key: 'node_name' },
     { title: '流程', dataIndex: 'definition_name', key: 'definition_name' },
@@ -56,12 +75,15 @@ export default function PendingTasks() {
       render: (v: string) => new Date(v).toLocaleString(),
     },
     {
-      title: '操作', key: 'action', width: 120,
+      title: '操作', key: 'action', width: 160,
       render: (_, record) => (
         <Space>
           <Button size="small" type="primary" onClick={() => { setCompleteModal(record); setOutcome('approved'); }}>
             审批
           </Button>
+          <Button size="small" onClick={() => { setDelegateModal(record); setDelegateTo(''); }}>
+            委派
+          </Button>
         </Space>
       ),
     },
@@ -92,6 +114,20 @@ export default function PendingTasks() {
           </Button>
         </Space>
       </Modal>
+      <Modal
+        title="委派任务"
+        open={!!delegateModal}
+        onOk={handleDelegate}
+        onCancel={() => { setDelegateModal(null); setDelegateTo(''); }}
+        okText="确认委派"
+      >
+        <p>任务: {delegateModal?.node_name}</p>
+        <Input
+          placeholder="输入目标用户 ID (UUID)"
+          value={delegateTo}
+          onChange={(e) => setDelegateTo(e.target.value)}
+        />
+      </Modal>
     </>
   );
 }