feat: 完善协议缴费分期、样本编码搜索与鸿蒙附件选择

支持移动端样本编码远程关键字检索、分期起始日刷新与鸿蒙微信附件选取，并同步收款账户选择、角色页与相关设计文档。

Co-authored-by: Cursor <cursoragent@cursor.com>

web-admin/src/utils/protocol-payment-installment.test.ts

@@ -0,0 +1,23 @@
+import { describe, it } from 'node:test'
+import assert from 'node:assert/strict'
+import { calcStandardFqDueDate } from './protocol-payment-installment'
+
+describe('calcStandardFqDueDate', () => {
+  it('builds six periods as start, +1 year, then +half year', () => {
+    const start = '20261021'
+    assert.deepEqual(
+      [0, 1, 2, 3, 4, 5].map((i) => calcStandardFqDueDate(start, i)),
+      ['20261021', '20271021', '20280421', '20281021', '20290421', '20291021']
+    )
+  })
+
+  it('clamps month-end when adding half a year', () => {
+    assert.equal(calcStandardFqDueDate('20260831', 2), '20280229')
+    assert.equal(calcStandardFqDueDate('20260831', 1), '20270831')
+  })
+
+  it('returns empty for an invalid start date', () => {
+    assert.equal(calcStandardFqDueDate('', 0), '')
+    assert.equal(calcStandardFqDueDate('2026-10-21', -1), '')
+  })
+})

web-admin/src/utils/protocol-payment-installment.ts

@@ -215,6 +215,30 @@ export function calcFqInstallmentDueDate(
   return base
 }
 
+/** 按日历加月，月末超出时落到该月最后一天 */
+function addCalendarMonthsYmd(dateStr: string, months: number): string {
+  const compact = String(dateStr || '').replace(/-/g, '')
+  if (compact.length !== 8 || !Number.isFinite(months)) return ''
+  const y = Number(compact.slice(0, 4))
+  const monthIndex = Number(compact.slice(4, 6)) - 1 + Math.trunc(months)
+  const ny = y + Math.floor(monthIndex / 12)
+  const nm = monthIndex % 12
+  const lastDay = new Date(ny, nm + 1, 0).getDate()
+  const nd = Math.min(Number(compact.slice(6, 8)), lastDay)
+  return `${ny}${String(nm + 1).padStart(2, '0')}${String(nd).padStart(2, '0')}`
+}
+
+/**
+ * 分期默认应缴日（与每期间隔、提前天数无关）：
+ * 第 1 期 = 开始日，第 2 期 = 第 1 期 + 1 年，第 3 期起每期在上一期基础上 + 半年。
+ */
+export function calcStandardFqDueDate(startDate: string, index: number): string {
+  const start = String(startDate || '').replace(/-/g, '')
+  if (start.length !== 8 || !Number.isInteger(index) || index < 0) return ''
+  if (index === 0) return start
+  return addCalendarMonthsYmd(start, 12 + (index - 1) * 6)
+}
+
 export function calcInstallmentDueAmounts(
   contractAmount: number | null | undefined,
   count: number