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

web/src/App.tsx

@@ -0,0 +1,89 @@
+import { createContext, useCallback, useContext, useEffect, useMemo, useState } from "react";
+import { Navigate, Route, Routes, useNavigate } from "react-router-dom";
+import { api, authExpired, session } from "./lib/client";
+import type { User, Workspace } from "./lib/types";
+import { LoginPage } from "./pages/Login";
+import { HomePage } from "./pages/Home";
+import { WorkspacePage } from "./pages/Workspace";
+import { JoinPage } from "./pages/Join";
+
+interface AuthState {
+  user: User | null;
+  workspaces: Workspace[];
+  loading: boolean;
+  reload: () => Promise<void>;
+  signOut: () => void;
+}
+
+const AuthContext = createContext<AuthState | null>(null);
+
+export function useAuth(): AuthState {
+  const ctx = useContext(AuthContext);
+  if (!ctx) throw new Error("useAuth 必须在 AuthProvider 内使用");
+  return ctx;
+}
+
+export function AuthProvider({ children }: { children: React.ReactNode }) {
+  const [user, setUser] = useState<User | null>(null);
+  const [workspaces, setWorkspaces] = useState<Workspace[]>([]);
+  const [loading, setLoading] = useState(true);
+  const navigate = useNavigate();
+
+  const reload = useCallback(async () => {
+    if (!session.access) {
+      setUser(null);
+      setWorkspaces([]);
+      setLoading(false);
+      return;
+    }
+    try {
+      const me = await api.get<{ user: User; workspaces: Workspace[] }>("/auth/me");
+      setUser(me.user);
+      setWorkspaces(me.workspaces);
+    } catch {
+      setUser(null);
+      setWorkspaces([]);
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    void reload();
+    const onExpired = () => {
+      setUser(null);
+      setWorkspaces([]);
+      navigate("/login", { replace: true });
+    };
+    authExpired.addEventListener("expired", onExpired);
+    return () => authExpired.removeEventListener("expired", onExpired);
+  }, [reload, navigate]);
+
+  const signOut = useCallback(() => {
+    session.clear();
+    setUser(null);
+    setWorkspaces([]);
+    navigate("/login", { replace: true });
+  }, [navigate]);
+
+  const value = useMemo<AuthState>(
+    () => ({ user, workspaces, loading, reload, signOut }),
+    [user, workspaces, loading, reload, signOut],
+  );
+
+  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
+}
+
+export function App() {
+  return (
+    <AuthProvider>
+      <Routes>
+        <Route path="/login" element={<LoginPage />} />
+        <Route path="/" element={<HomePage />} />
+        <Route path="/w/:wsId" element={<WorkspacePage />} />
+        <Route path="/join/:wsId/:code" element={<JoinPage />} />
+        <Route path="*" element={<Navigate to="/" replace />} />
+      </Routes>
+    </AuthProvider>
+  );
+}