feat(server): MinIO/S3 对象存储兼容（F21）

- 新增 storage 抽象：local 与 s3: 前缀兼容（不改 schema）
- invoice-pool 上传/预览/ocr 读取适配 S3/MinIO
- trialrun compose 增加 minio profile + env 示例与 runbook 指引
- 更新 README 与 v3 CSV 状态推进

server/package.json

@@ -26,6 +26,7 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
+    "@aws-sdk/client-s3": "^3.985.0",
     "@fastify/cookie": "^11.0.2",
     "@fastify/cors": "^11.2.0",
     "@fastify/helmet": "^13.0.2",