fix(worker-platform): 修复对已冻结打手调级时误报冻结原因必填的问题

- 做了什么：
  1. 后端 reviewAdminWorkerUser 中优化 freezeReason 校验条件：区分是否为新变为 rejected 状态，若账号原本已处于冻结态且本次仅调整等级未变动状态，直接沿用已有冻结原因，不再强制要求传 freezeReason；
  2. 前端 submitLevel 在提交调级时补充传递打手既有的 freezeReason；
  3. 后端新增对应测试用例确保后续回归。
- 为什么：
  当打手处于冻结状态（rejected）时，管理员对其执行调级操作因未携带 freezeReason 触发了冻结原因校验错误，导致调级失败。
- 验证方式：
  运行 npm run check（671 项测试全绿，类型与构建检查通过）。

apps/backend/src/services/worker-platform/admin-worker-user-service.ts

@@ -77,10 +77,17 @@ export async function reviewAdminWorkerUser(
   operatorUsername: string = '',
 ) {
   const worker = await getRequiredWorker(workerId)
-  const status = normalizeReviewStatus(payload.status)
+  const status =
+    payload.status !== undefined && payload.status !== null
+      ? normalizeReviewStatus(payload.status)
+      : worker.status
+  const isNewlyRejected = status === 'rejected' && worker.status !== 'rejected'
+  const rawFreezeReason = payload.freezeReason ?? payload.freeze_reason
   const freezeReason =
     status === 'rejected'
-      ? normalizeWorkerFreezeReason(payload.freezeReason ?? payload.freeze_reason)
+      ? isNewlyRejected || rawFreezeReason !== undefined
+        ? normalizeWorkerFreezeReason(rawFreezeReason ?? worker.frozen_reason)
+        : worker.frozen_reason || ''
       : worker.frozen_reason || ''
   const workerType = normalizeWorkerType(payload.workerType ?? payload.worker_type)
   const requestedLevelId = normalizeOptionalId(payload.levelId)

apps/backend/src/services/worker-platform/worker-platform-service.test.ts

@@ -3050,3 +3050,12 @@ test('接单排行榜必须有短缓存（单次全表聚合 277MB/742ms，独
     '排行榜缓存键必须包含 workerId 与 period',
   )
 })
+
+test('已冻结打手调级或变更资料不应因未传 freezeReason 报错', async () => {
+  const { readFile } = await import('node:fs/promises')
+  const src = await readFile(new URL('./admin-worker-user-service.ts', import.meta.url), 'utf8')
+  assert.ok(
+    src.includes('isNewlyRejected'),
+    '必须区分是否为新冻结，防止已冻结账号调级时抛出 freeze_reason 必填错误',
+  )
+})