feat: 培训/绩效/违纪员工端签收+管理端签字状态只读化

- 后端: portal新增培训/绩效/违纪列表查看+签收接口，签收时创建证据链
- 管理端: 弹窗去掉HR手动签字勾选，改为只读显示签字状态
- 绩效列表新增签字状态列
- 员工端: 新增MyRecords页面，支持培训签收/拒绝、绩效签字、违纪签字
- 员工端导航新增'我的记录'入口
- EvidenceCategory新增TRAINING/PERFORMANCE类型

frontend/src/pages/roster/DisciplinaryRecords.tsx

@@ -193,7 +193,6 @@ function DisciplinaryForm({ employees, record, onSubmit, onClose }: {
     severity: record?.severity || 'WARNING',
     action: record?.action || 'ORAL_WARNING',
     actionDetail: record?.actionDetail || '',
-    employeeAck: record?.employeeAck || false,
     witness: record?.witness || '',
   })
 
@@ -263,10 +262,18 @@ function DisciplinaryForm({ employees, record, onSubmit, onClose }: {
             <Label>见证人</Label>
             <Input value={form.witness} onChange={(e) => setForm({ ...form, witness: e.target.value })} placeholder="见证人（选填）" />
           </div>
-          <label className="flex items-center gap-2">
-            <input type="checkbox" checked={form.employeeAck} onChange={(e) => setForm({ ...form, employeeAck: e.target.checked })} />
-            <span className="text-sm">员工已签字确认</span>
-          </label>
+          {record && (
+            <div>
+              <Label>签字状态</Label>
+              <div className="text-sm text-gray-600">
+                {record.employeeAck ? (
+                  <span className="text-green-600">已签字（{record.ackDate ? new Date(record.ackDate).toLocaleDateString('zh-CN') : ''}）</span>
+                ) : (
+                  <span className="text-amber-600">待签字 <span className="text-xs text-gray-400 ml-1">由员工在员工端签字确认</span></span>
+                )}
+              </div>
+            </div>
+          )}
           <div className="flex justify-end gap-2 pt-2">
             <Button variant="secondary" size="sm" onClick={onClose}>取消</Button>
             <Button size="sm" onClick={() => onSubmit(form)} disabled={!form.employeeId || !form.description}>保存</Button>