feat: 后端 CRUD 完成（episodes + yearly_targets + users 管理 API）

backend/app/schemas/user_admin.py

@@ -0,0 +1,33 @@
+"""
+用户管理 Schema — 管理员 CRUD（仅 zhipianren 可用）
+"""
+
+from pydantic import BaseModel, ConfigDict
+
+from app.models.user import UserRole
+
+
+class UserCreate(BaseModel):
+    username: str
+    display_name: str
+    password: str
+    role: UserRole
+    profile_text: str | None = None
+
+
+class UserUpdate(BaseModel):
+    display_name: str | None = None
+    role: UserRole | None = None
+    profile_text: str | None = None
+    is_active: bool | None = None
+
+
+class UserResponse(BaseModel):
+    id: int
+    username: str
+    display_name: str
+    role: UserRole
+    profile_text: str | None = None
+    is_active: bool = True
+
+    model_config = ConfigDict(from_attributes=True)