feat: 新增 MinIO 对象存储与算力节点缓存预下载

- 后端新增 storage 模块（minio_store），支持 MinIO 预签名 URL 上传与对象管理
- config 新增 MinIO 及存储等待相关配置项
- 算力节点新增 /compute/cache/prepare 缓存预下载接口（带校验和原子落盘）
- 算力节点健康接口增加存储可用性探针
- SQL 迁移补充资源存储相关表结构
- Docker 新增 minio 服务与后端 minio 配置
- 补充 minio-compute-cache-plan 设计文档

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/db/platform_store.py

@@ -505,6 +505,20 @@ class PlatformStore:
             )
             self._ensure_columns(conn, "gpus", {"last_seen_at": "TEXT"})
             self._ensure_columns(conn, "fine_tune_tasks", {"compute_job_id": "TEXT"})
+            self._ensure_columns(
+                conn,
+                "sessions",
+                {
+                    "username": "TEXT",
+                    "login_at": "TEXT",
+                    "logout_at": "TEXT",
+                    "duration_seconds": "INTEGER",
+                    "issued_at": "TEXT",
+                    "expires_at": "TEXT",
+                    "ip": "TEXT",
+                    "create_time": "TEXT",
+                },
+            )
             self._ensure_columns(
                 conn,
                 "trained_models",
@@ -525,7 +539,12 @@ class PlatformStore:
                 },
             )
             schema_dir = Path(__file__).with_name("sql")
-            for extra in ("002_governance.sql", "003_tenant_quota.sql", "004_permissions.sql"):
+            for extra in (
+                "002_governance.sql",
+                "003_model_path_governance.sql",
+                "003_tenant_quota.sql",
+                "004_permissions.sql",
+            ):
                 extra_path = schema_dir / extra
                 if extra_path.exists():
                     conn.executescript(extra_path.read_text(encoding="utf-8"))
@@ -2863,6 +2882,54 @@ class PlatformStore:
                     result.append(dict(row))
             return result
 
+    def create_storage_object(self, payload: dict[str, Any]) -> dict[str, Any]:
+        object_id = str(payload.get("id") or new_id("object"))
+        with self.connect() as conn:
+            conn.execute(
+                """
+                INSERT INTO storage_objects
+                (id, resource_type, resource_id, version_id, bucket, object_key, file_name,
+                 content_type, checksum_sha256, byte_size, status, created_by, create_time)
+                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                ON CONFLICT (resource_type, resource_id, version_id, object_key)
+                DO UPDATE SET file_name=EXCLUDED.file_name, content_type=EXCLUDED.content_type,
+                    checksum_sha256=EXCLUDED.checksum_sha256, byte_size=EXCLUDED.byte_size,
+                    status=EXCLUDED.status, created_by=EXCLUDED.created_by
+                """,
+                (
+                    object_id, payload["resource_type"], payload["resource_id"], payload["version_id"],
+                    payload["bucket"], payload["object_key"], payload.get("file_name"), payload.get("content_type"),
+                    payload.get("checksum_sha256"), int(payload.get("byte_size") or 0), payload.get("status", "pending"),
+                    payload.get("created_by"), payload.get("create_time") or utcnow(),
+                ),
+            )
+            row = conn.execute(
+                "SELECT * FROM storage_objects WHERE resource_type=? AND resource_id=? AND version_id=? AND object_key=?",
+                (payload["resource_type"], payload["resource_id"], payload["version_id"], payload["object_key"]),
+            ).fetchone()
+            return dict(row)
+
+    def storage_objects_for_resource(self, resource_type: str, resource_id: str) -> list[dict[str, Any]]:
+        with self.connect() as conn:
+            rows = conn.execute(
+                "SELECT * FROM storage_objects WHERE resource_type=? AND resource_id=? AND status='available' ORDER BY version_id, object_key",
+                (resource_type, resource_id),
+            ).fetchall()
+            return [dict(row) for row in rows]
+
+    def update_storage_object(self, object_id: str, payload: dict[str, Any]) -> dict[str, Any]:
+        allowed = {"status", "checksum_sha256", "byte_size", "content_type"}
+        fields = {key: value for key, value in payload.items() if key in allowed}
+        if fields:
+            assignments = ", ".join(f"{key}=?" for key in fields)
+            with self.connect() as conn:
+                conn.execute(f"UPDATE storage_objects SET {assignments} WHERE id=?", (*fields.values(), object_id))
+        with self.connect() as conn:
+            row = conn.execute("SELECT * FROM storage_objects WHERE id=?", (object_id,)).fetchone()
+            if not row:
+                raise KeyError(object_id)
+            return dict(row)
+
     def update_resource_replica_sync_result(
         self,
         replica_id: str,