prepare fastapi root layout for server deployment

app/core/context.py

@@ -0,0 +1,25 @@
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class UserContext:
+    """用户上下文：承载 Django 用户中心认证后的用户 ID 和入口元数据。"""
+
+    user_id: str
+    tenant_id: str | None = None
+    role: str | None = None
+    class_id: str | None = None
+    institution_id: int | None = None
+    department_id: int | None = None
+    entry_scene: str | None = None
+    request_id: str | None = None
+    ip_address: str | None = None
+    user_agent: str | None = None
+    username: str | None = None
+    display_name: str | None = None
+    phone: str | None = None
+    major: str | None = None
+    training_stage: str | None = None
+    learning_target: str | None = None
+    auth_source: str = "django_user_center"
+    profile: dict | None = None