feat(m0): 后端骨架 + Web/安卓前端骨架 + 设计文档

- backend: FastAPI 应用工厂、统一错误信封、JWT、短信登录、工作区/成员/邀请、幂等中间件
- alembic 0001: workspace/member/invitation/audit_log/app_user + RLS 策略 + 双角色 GRANT
- tests: 认证/工作区/租户隔离/幂等 四组用例（尚未在本机执行）
- web: React18+Vite 骨架（登录、工作区、邀请落地页）
- android: Compose 骨架（登录、工作区列表）
- 2.Design: PRODUCT-PLAN / ROADMAP-M0-M1 / NAMING / DEVELOPMENT

backend/app/api/schemas.py

@@ -0,0 +1,67 @@
+"""对外输出模型。字段命名一次定死，客户端按契约生成。"""
+
+from __future__ import annotations
+
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class UserOut(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    phone: str = Field(description="已打码的手机号，如 138****8000")
+    nickname: str
+    created_at: datetime
+
+
+class TokenOut(BaseModel):
+    access_token: str
+    refresh_token: str
+    token_type: str = "bearer"
+    expires_in: int
+
+
+class LoginOut(BaseModel):
+    user: UserOut
+    tokens: TokenOut
+
+
+class WorkspaceOut(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    name: str
+    slug: str
+    plan: str
+    role: str = ""
+    created_at: datetime
+
+
+class MemberOut(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    user_id: uuid.UUID
+    role: str
+    status: str
+    nickname: str = ""
+    phone: str = ""
+    joined_at: datetime
+
+
+class InvitationOut(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    code: str
+    role: str
+    expires_at: datetime
+    accepted_at: datetime | None = None
+
+
+class MeOut(BaseModel):
+    user: UserOut
+    workspaces: list[WorkspaceOut]