添加Docker自包含部署分支

- 新增 Seg_Server_Docker 自包含部署内容，包含前后端、FastAPI、Celery、PostgreSQL、Redis、MinIO、演示视频和 DICOM 数据。

- 保留 demo 数据以支持恢复演示出厂设置，排除 SAM 2.1 .pt 权重并在 README 中补充下载命令。

- 补充 GPU 部署、backend/worker 镜像复用、frpc/frps + NPM 公网域名反代部署说明。

- 在 .env/.env.example 中用 # XXXX 标注局域网和公网域名部署需要修改的配置项。

- 添加部署分支 .gitignore，忽略本地模型权重、构建产物、缓存和日志。

backend/minio_client.py

@@ -0,0 +1,142 @@
+"""MinIO client wrapper for object storage operations."""
+
+import io
+import logging
+from typing import Optional
+
+from minio import Minio
+from minio.error import S3Error
+
+from config import settings
+
+logger = logging.getLogger(__name__)
+
+BUCKET_NAME = "seg-media"
+
+_minio_client: Optional[Minio] = None
+_minio_public_client: Optional[Minio] = None
+
+
+def get_minio_client() -> Minio:
+    """Return a singleton MinIO client instance."""
+    global _minio_client
+    if _minio_client is None:
+        _minio_client = Minio(
+            settings.minio_endpoint,
+            access_key=settings.minio_access_key,
+            secret_key=settings.minio_secret_key,
+            secure=settings.minio_secure,
+        )
+    return _minio_client
+
+
+def get_minio_public_client() -> Minio:
+    """Return a MinIO client configured for browser-facing presigned URLs."""
+    global _minio_public_client
+    if _minio_public_client is None:
+        endpoint = settings.minio_public_endpoint or settings.minio_endpoint
+        _minio_public_client = Minio(
+            endpoint,
+            access_key=settings.minio_access_key,
+            secret_key=settings.minio_secret_key,
+            secure=settings.minio_secure,
+        )
+    return _minio_public_client
+
+
+def ensure_bucket_exists() -> None:
+    """Create the bucket if it does not already exist."""
+    client = get_minio_client()
+    try:
+        if not client.bucket_exists(BUCKET_NAME):
+            client.make_bucket(BUCKET_NAME)
+            logger.info("Created MinIO bucket: %s", BUCKET_NAME)
+        else:
+            logger.info("MinIO bucket %s already exists", BUCKET_NAME)
+    except S3Error as exc:
+        logger.error("MinIO bucket check/creation failed: %s", exc)
+        raise
+
+
+def upload_file(
+    object_name: str,
+    data: bytes,
+    content_type: str = "application/octet-stream",
+    length: int = -1,
+) -> str:
+    """Upload bytes to MinIO and return the object name.
+
+    Args:
+        object_name: Destination path inside the bucket.
+        data: Raw bytes or a file-like object.
+        content_type: MIME type of the object.
+        length: Object size; -1 for unknown (uses chunked upload).
+
+    Returns:
+        The object name (same as input).
+    """
+    client = get_minio_client()
+    if isinstance(data, bytes):
+        data = io.BytesIO(data)
+        length = len(data.getvalue())
+
+    try:
+        client.put_object(
+            BUCKET_NAME,
+            object_name,
+            data,
+            length=length,
+            content_type=content_type,
+        )
+        logger.info("Uploaded to MinIO: %s", object_name)
+        return object_name
+    except S3Error as exc:
+        logger.error("MinIO upload failed: %s", exc)
+        raise
+
+
+from datetime import timedelta
+
+def get_presigned_url(
+    object_name: str,
+    expires: int = 3600,
+    method: str = "GET",
+) -> str:
+    """Generate a presigned URL for an object.
+
+    Args:
+        object_name: Path inside the bucket.
+        expires: Expiration time in seconds (default 1 hour).
+        method: HTTP method (GET or PUT).
+
+    Returns:
+        Presigned URL string.
+    """
+    client = get_minio_public_client()
+    try:
+        url = client.get_presigned_url(method, BUCKET_NAME, object_name, expires=timedelta(seconds=expires))
+        return url
+    except S3Error as exc:
+        logger.error("MinIO presigned URL failed: %s", exc)
+        raise
+
+
+def download_file(object_name: str) -> bytes:
+    """Download an object from MinIO and return its bytes.
+
+    Args:
+        object_name: Path inside the bucket.
+
+    Returns:
+        Raw bytes of the object.
+    """
+    client = get_minio_client()
+    try:
+        response = client.get_object(BUCKET_NAME, object_name)
+        data = response.read()
+        response.close()
+        response.release_conn()
+        return data
+    except S3Error as exc:
+        logger.error("MinIO download failed: %s", exc)
+        raise