feat(models): 组织、用户、角色、客户、会话与消息模型

按组织边界定义数据关系，补齐仓储层与通用工具，迁移脚本可重复执行。

backend/app/models/schemas/user.py

@@ -0,0 +1,145 @@
+"""
+Copyright 2024-2026 ChatterMate
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+from pydantic import BaseModel, EmailStr, field_serializer, field_validator
+from typing import Optional, List
+from uuid import UUID
+from datetime import datetime
+
+from app.core.s3 import sign_s3_url
+from app.core.security import validate_password_strength
+
+from app.models.schemas.role import RoleResponse
+
+
+
+class UserBase(BaseModel):
+    email: EmailStr
+    full_name: str
+    is_active: bool = True
+    profile_pic: Optional[str] = None
+    is_online: bool = False
+    last_seen: Optional[datetime] = None
+
+
+class ChatScopeFields(BaseModel):
+    """The two chat-scope toggles on the user form.
+
+    Both default to None, meaning "whatever the chosen role already grants".
+    A client that predates these fields keeps its old behaviour; the form
+    sends explicit values because it renders the role's current scope.
+    """
+    see_all_ai_chats: Optional[bool] = None
+    see_all_org_chats: Optional[bool] = None
+
+
+class UserCreate(UserBase, ChatScopeFields):
+    password: str
+    role_id: int
+
+    @field_validator('password')
+    @classmethod
+    def _check_strength(cls, value: str) -> str:
+        # The password an admin picks for a new teammate clears the same bar as
+        # one set by a reset — otherwise the policy is one invite away from
+        # being bypassed.
+        return validate_password_strength(value)
+
+
+class UserUpdate(ChatScopeFields):
+    email: Optional[EmailStr] = None
+    full_name: Optional[str] = None
+    password: Optional[str] = None
+    is_active: Optional[bool] = None
+    current_password: Optional[str] = None
+    role_id: Optional[int] = None
+    profile_pic: Optional[str] = None
+    is_online: Optional[bool] = None
+
+class TeammateResponse(BaseModel):
+    """A colleague as the inbox needs them: enough to pick one and render them.
+
+    No role, no permissions, no timestamps — an agent listing who they can hand
+    a chat to has no business reading the org's permission matrix, which is
+    what UserResponse would give them.
+    """
+    id: UUID
+    full_name: Optional[str] = None
+    email: EmailStr
+    profile_pic: Optional[str] = None
+    is_online: Optional[bool] = False
+
+    @field_serializer('profile_pic')
+    def _sign_profile_pic(self, v: Optional[str]) -> Optional[str]:
+        return sign_s3_url(v) if v else v
+
+    class Config:
+        from_attributes = True
+
+
+class AdminPasswordReset(BaseModel):
+    """An admin setting a new password for someone else in their organization.
+
+    No current_password: the admin does not know it — that is the point of a
+    reset. The policy check lives here because nobody is around to see the
+    form's strength meter when the call arrives from a script.
+    """
+    new_password: str
+
+    @field_validator('new_password')
+    @classmethod
+    def _check_strength(cls, value: str) -> str:
+        return validate_password_strength(value)
+
+
+class UserStatusUpdate(BaseModel):
+    is_online: bool
+
+class UserGroupResponse(BaseModel):
+    name: str
+    description: Optional[str] = None
+
+class UserResponse(UserBase):
+    id: UUID
+    organization_id: Optional[UUID] = None
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+    is_online: Optional[bool] = None
+    last_seen: Optional[datetime] = None
+    profile_pic: Optional[str] = None
+    is_active: Optional[bool] = None
+    groups: Optional[List[UserGroupResponse]] = None    
+    role: Optional[RoleResponse] = None
+
+    @field_serializer('profile_pic')
+    def _sign_profile_pic(self, v: Optional[str]) -> Optional[str]:
+        """Sign on the way out, every response — never stored signed."""
+        return sign_s3_url(v) if v else v
+
+    class Config:
+        from_attributes = True
+
+
+
+
+class TokenResponse(BaseModel):
+    access_token: str
+    refresh_token: str
+    token_type: str
+    user: UserResponse
+
+    class Config:
+        from_attributes = True