Function evaluateUpload

evaluateUpload(
file: UploadCandidate,
constraint: UploadConstraint,
): UploadVerdict
对上传候选文件过闸（先尺寸、后类型）。
Parameters
- file: UploadCandidate
  待校验的上传候选。
- constraint: UploadConstraint
  尺寸上限 + MIME 白名单。
Returns UploadVerdict
裁决结果（通过或携拒因）。
- Defined in apps/api/src/modules/storage/domain/policies/upload.policy.ts:48