优化: 重新入职弹窗对齐添加员工

1. 移除孕期/医疗期/工伤复选框（重新入职自动重置为false）
2. 缺省入职日期和合同开始日期为今天，默认3年合同结束日期
3. 签约时长与合同结束日期双向自动计算
4. 试用期长度按劳动合同法校验+试用期工资必填及80%校验
5. 试用期工资校验使用员工已有月工资作为基准

frontend/src/pages/Roster.tsx

@@ -789,26 +789,101 @@ function RehireModal({ employee, onClose, onSubmit, loading, error }: {
   loading: boolean
   error: any
 }) {
+  const todayStr = new Date().toISOString().slice(0, 10)
+  const defaultEndDate = (() => {
+    const d = new Date()
+    d.setFullYear(d.getFullYear() + 3)
+    d.setDate(d.getDate() - 1)
+    return d.toISOString().slice(0, 10)
+  })()
   const [form, setForm] = useState({
-    hireDate: new Date().toISOString().slice(0, 10),
-    isPregnant: false,
-    isInMedicalPeriod: false,
-    isWorkInjured: false,
+    hireDate: todayStr,
     contractType: 'FIXED' as 'FIXED' | 'UNFIXED' | 'UNSIGNED',
     signDate: '',
-    startDate: '',
-    endDate: '',
+    startDate: todayStr,
+    endDate: defaultEndDate,
     contractYears: 3,
     probationMonths: 0,
     probationSalary: 0,
   })
 
+  // 计算合同月数
+  const contractMonths = (() => {
+    if (form.contractType !== 'FIXED' || !form.startDate) return 0
+    if (form.endDate) {
+      const start = new Date(form.startDate)
+      const end = new Date(form.endDate)
+      return Math.round((end.getTime() - start.getTime()) / (1000 * 60 * 60 * 24 * 30.44))
+    }
+    return form.contractYears * 12
+  })()
+
+  // 试用期上限（劳动合同法第19条）
+  const probationMax = (() => {
+    if (contractMonths >= 36) return 6
+    if (contractMonths >= 12) return 2
+    if (contractMonths >= 3) return 1
+    return 0
+  })()
+
+  const probationError = (() => {
+    if (form.probationMonths <= 0) return ''
+    if (contractMonths > 0 && contractMonths < 3) return '合同不足3个月，不得约定试用期'
+    if (form.probationMonths > probationMax) return `合同${contractMonths}个月，试用期最多${probationMax}个月`
+    return ''
+  })()
+
+  const monthlySalaryNum = employee?.monthlySalary || 0
+  const probationSalaryError = (() => {
+    if (form.probationMonths <= 0) return ''
+    if (form.probationSalary <= 0) return '有试用期时试用期工资必填'
+    if (monthlySalaryNum > 0 && form.probationSalary < monthlySalaryNum * 0.8) {
+      return `试用期工资不得低于转正工资的80%（最低¥${(monthlySalaryNum * 0.8).toFixed(0)}）`
+    }
+    return ''
+  })()
+
+  // 合同结束日期自动计算
+  const handleContractYearsChange = (years: number) => {
+    if (!form.startDate || years <= 0) {
+      setForm({ ...form, contractYears: years, endDate: '' })
+      return
+    }
+    const start = new Date(form.startDate)
+    const end = new Date(start)
+    end.setFullYear(end.getFullYear() + years)
+    end.setDate(end.getDate() - 1)
+    setForm({ ...form, contractYears: years, endDate: end.toISOString().slice(0, 10) })
+  }
+
+  // 合同结束日期变更 → 自动计算签约年限
+  const handleEndDateChange = (endDate: string) => {
+    if (!form.startDate || !endDate) {
+      setForm({ ...form, endDate, contractYears: 0 })
+      return
+    }
+    const start = new Date(form.startDate)
+    const end = new Date(endDate)
+    const months = Math.round((end.getTime() - start.getTime()) / (1000 * 60 * 60 * 24 * 30.44))
+    setForm({ ...form, endDate, contractYears: Math.max(1, Math.round(months / 12)) })
+  }
+
+  // 开始日期变更 → 重新计算结束日期
+  const handleStartDateChange = (startDate: string) => {
+    if (form.contractType === 'FIXED' && form.contractYears > 0 && startDate) {
+      const start = new Date(startDate)
+      const end = new Date(start)
+      end.setFullYear(end.getFullYear() + form.contractYears)
+      end.setDate(end.getDate() - 1)
+      setForm({ ...form, startDate, endDate: end.toISOString().slice(0, 10) })
+    } else {
+      setForm({ ...form, startDate })
+    }
+  }
+
   const handleSubmit = () => {
     const data: any = {
       hireDate: new Date(form.hireDate).toISOString(),
-      isPregnant: form.isPregnant,
-      isInMedicalPeriod: form.isInMedicalPeriod,
-      isWorkInjured: form.isWorkInjured,
     }
     if (form.contractType !== 'UNSIGNED' && form.startDate) {
       data.contract = {
@@ -824,78 +899,79 @@ function RehireModal({ employee, onClose, onSubmit, loading, error }: {
     onSubmit(data)
   }
 
+  const canSubmit = form.hireDate
+    && (form.contractType === 'UNSIGNED' || form.startDate)
+    && !probationError && !probationSalaryError
+
   return (
     <Modal open onClose={onClose} title={`重新入职 - ${employee.name}`}>
       <div className="space-y-3">
         <div className="bg-blue-50 text-blue-700 text-xs px-3 py-2 rounded-md">
-          复用员工已有基本信息（姓名、部门、手机等），只需填写新入职日期和劳动合同。
+          复用员工已有基本信息（姓名、部门、身份证号等），只需填写新入职日期和劳动合同。
+        </div>
+        <div className="grid grid-cols-2 gap-3">
+          <div>
+            <Label>员工</Label>
+            <div className="text-xs text-gray-600 py-1.5">{employee.name}</div>
+          </div>
+          <div>
+            <Label>部门</Label>
+            <div className="text-xs text-gray-600 py-1.5">{employee.department}</div>
+          </div>
         </div>
         <div>
-          <Label>员工</Label>
-          <div className="text-xs text-gray-600">{employee.name} - {employee.department}</div>
-        </div>
-        <div>
-          <Label>新入职日期</Label>
-          <Input
-            type="date"
-            value={form.hireDate}
-            onChange={(e) => setForm({ ...form, hireDate: e.target.value })}
-          />
-        </div>
-        <div className="flex gap-4 text-xs">
-          <label className="flex items-center gap-1">
-            <input type="checkbox" checked={form.isPregnant} onChange={(e) => setForm({ ...form, isPregnant: e.target.checked })} />
-            孕期
-          </label>
-          <label className="flex items-center gap-1">
-            <input type="checkbox" checked={form.isInMedicalPeriod} onChange={(e) => setForm({ ...form, isInMedicalPeriod: e.target.checked })} />
-            医疗期
-          </label>
-          <label className="flex items-center gap-1">
-            <input type="checkbox" checked={form.isWorkInjured} onChange={(e) => setForm({ ...form, isWorkInjured: e.target.checked })} />
-            工伤
-          </label>
+          <Label>新入职日期 *</Label>
+          <Input type="date" value={form.hireDate} onChange={(e) => setForm({ ...form, hireDate: e.target.value })} />
         </div>
         <div className="border-t pt-3">
-          <Label>劳动合同</Label>
-          <Select value={form.contractType} onChange={(e) => setForm({ ...form, contractType: e.target.value as any })}>
+          <Label>合同类型</Label>
+          <Select value={form.contractType} onChange={(e) => setForm({ ...form, contractType: e.target.value as any, endDate: e.target.value === 'UNFIXED' ? '' : form.endDate })}>
             <option value="FIXED">固定期限</option>
             <option value="UNFIXED">无固定期限</option>
             <option value="UNSIGNED">暂不签订</option>
           </Select>
         </div>
         {form.contractType !== 'UNSIGNED' && (
-          <div className="space-y-2">
-            <div className="grid grid-cols-2 gap-2">
+          <div className="space-y-3">
+            <div className="grid grid-cols-2 gap-3">
               <div>
                 <Label>签订日期</Label>
                 <Input type="date" value={form.signDate} onChange={(e) => setForm({ ...form, signDate: e.target.value })} />
+                <div className="text-xs text-gray-400 mt-0.5">留空表示尚未签订</div>
               </div>
-              <div>
-                <Label>合同起始日</Label>
-                <Input type="date" value={form.startDate} onChange={(e) => setForm({ ...form, startDate: e.target.value })} />
-              </div>
+              <div><Label>合同开始日期 *</Label><Input type="date" value={form.startDate} onChange={(e) => handleStartDateChange(e.target.value)} /></div>
             </div>
             {form.contractType === 'FIXED' && (
-              <div className="grid grid-cols-2 gap-2">
-                <div>
-                  <Label>合同到期日</Label>
-                  <Input type="date" value={form.endDate} onChange={(e) => setForm({ ...form, endDate: e.target.value })} />
+              <>
+                <div className="grid grid-cols-2 gap-3">
+                  <div>
+                    <Label>签约时长（年）</Label>
+                    <Input type="number" value={form.contractYears} onChange={(e) => handleContractYearsChange(parseInt(e.target.value) || 0)} min={1} />
+                  </div>
+                  <div>
+                    <Label>合同结束日期</Label>
+                    <Input type="date" value={form.endDate} onChange={(e) => handleEndDateChange(e.target.value)} />
+                  </div>
                 </div>
-                <div>
-                  <Label>合同年限</Label>
-                  <Input type="number" value={form.contractYears} onChange={(e) => setForm({ ...form, contractYears: parseInt(e.target.value) || 3 })} />
-                </div>
-              </div>
+                <div className="text-xs text-gray-400">修改签约时长自动计算结束日期，修改结束日期自动计算签约时长</div>
+              </>
             )}
-            <div className="grid grid-cols-2 gap-2">
+            <div className="grid grid-cols-2 gap-3">
               <div>
                 <Label>试用期（月）</Label>
-                <Input type="number" value={form.probationMonths} onChange={(e) => setForm({ ...form, probationMonths: parseInt(e.target.value) || 0 })} />
+                <Input type="number" value={form.probationMonths} onChange={(e) => setForm({ ...form, probationMonths: parseInt(e.target.value) || 0 })} min={0} max={6} />
+                {contractMonths > 0 && (
+                  <div className="text-xs text-gray-400 mt-0.5">法定上限：{probationMax}个月</div>
+                )}
+                {probationError && <div className="text-xs text-danger mt-0.5">{probationError}</div>}
               </div>
               <div>
-                <Label>试用期工资</Label>
-                <Input type="number" value={form.probationSalary} onChange={(e) => setForm({ ...form, probationSalary: parseFloat(e.target.value) || 0 })} />
+                <Label>试用期工资{form.probationMonths > 0 ? ' *' : ''}</Label>
+                <Input type="number" value={form.probationSalary} onChange={(e) => setForm({ ...form, probationSalary: parseFloat(e.target.value) || 0 })} disabled={form.probationMonths <= 0} />
+                {monthlySalaryNum > 0 && form.probationMonths > 0 && (
+                  <div className="text-xs text-gray-400 mt-0.5">不低于转正工资80%（≥¥{(monthlySalaryNum * 0.8).toFixed(0)}）</div>
+                )}
+                {probationSalaryError && <div className="text-xs text-danger mt-0.5">{probationSalaryError}</div>}
               </div>
             </div>
           </div>
@@ -907,9 +983,7 @@ function RehireModal({ employee, onClose, onSubmit, loading, error }: {
         )}
         <div className="flex justify-end gap-2 pt-2">
           <Button variant="secondary" onClick={onClose}>取消</Button>
-          <Button onClick={handleSubmit} disabled={loading}>
-            {loading ? '提交中...' : '确认入职'}
-          </Button>
+          <Button onClick={handleSubmit} disabled={loading || !canSubmit}>{loading ? '提交中...' : '确认入职'}</Button>
         </div>
       </div>
     </Modal>