feat: add AuthContext, RequireAuth guard, and Darkwatch app routing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/App.tsx

@@ -1,22 +1,53 @@
 import { BrowserRouter, Routes, Route } from "react-router-dom";
+import { AuthProvider } from "./context/AuthContext";
+import RequireAuth from "./components/RequireAuth";
 import CampaignList from "./pages/CampaignList";
 import CampaignView from "./pages/CampaignView";
+import LoginPage from "./pages/LoginPage";
+import RegisterPage from "./pages/RegisterPage";
+import JoinPage from "./pages/JoinPage";
 import ThemeToggle from "./components/ThemeToggle";
 import styles from "./App.module.css";
 
 export default function App() {
   return (
     <BrowserRouter>
-      <div className={styles.app}>
-        <header className={styles.header}>
-          <h1>Shadowdark</h1>
-          <ThemeToggle />
-        </header>
-        <Routes>
-          <Route path="/" element={<CampaignList />} />
-          <Route path="/campaign/:id" element={<CampaignView />} />
-        </Routes>
-      </div>
+      <AuthProvider>
+        <div className={styles.app}>
+          <header className={styles.header}>
+            <h1>Darkwatch</h1>
+            <ThemeToggle />
+          </header>
+          <Routes>
+            <Route path="/login" element={<LoginPage />} />
+            <Route path="/register" element={<RegisterPage />} />
+            <Route
+              path="/join/:token"
+              element={
+                <RequireAuth>
+                  <JoinPage />
+                </RequireAuth>
+              }
+            />
+            <Route
+              path="/"
+              element={
+                <RequireAuth>
+                  <CampaignList />
+                </RequireAuth>
+              }
+            />
+            <Route
+              path="/campaign/:id"
+              element={
+                <RequireAuth>
+                  <CampaignView />
+                </RequireAuth>
+              }
+            />
+          </Routes>
+        </div>
+      </AuthProvider>
     </BrowserRouter>
   );
 }

client/src/components/RequireAuth.tsx

@@ -0,0 +1,10 @@
+import { Navigate } from "react-router-dom";
+import type { ReactNode } from "react";
+import { useAuth } from "../context/AuthContext";
+
+export default function RequireAuth({ children }: { children: ReactNode }) {
+  const { user, loading } = useAuth();
+  if (loading) return null;
+  if (!user) return <Navigate to="/login" replace />;
+  return <>{children}</>;
+}

client/src/context/AuthContext.tsx

@@ -0,0 +1,45 @@
+import { createContext, useContext, useEffect, useState } from "react";
+import type { ReactNode } from "react";
+import { getMe, logout as apiLogout } from "../api";
+import type { AuthUser } from "../api";
+
+interface AuthContextValue {
+  user: AuthUser | null;
+  loading: boolean;
+  setUser: (user: AuthUser | null) => void;
+  logout: () => Promise<void>;
+}
+
+const AuthContext = createContext<AuthContextValue>({
+  user: null,
+  loading: true,
+  setUser: () => {},
+  logout: async () => {},
+});
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [user, setUser] = useState<AuthUser | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    getMe()
+      .then(setUser)
+      .catch(() => setUser(null))
+      .finally(() => setLoading(false));
+  }, []);
+
+  async function logout() {
+    await apiLogout().catch(() => {});
+    setUser(null);
+  }
+
+  return (
+    <AuthContext.Provider value={{ user, loading, setUser, logout }}>
+      {children}
+    </AuthContext.Provider>
+  );
+}
+
+export function useAuth() {
+  return useContext(AuthContext);
+}

client/src/pages/JoinPage.tsx

@@ -0,0 +1,3 @@
+export default function JoinPage() {
+  return <div>Join</div>;
+}

client/src/pages/LoginPage.tsx

@@ -0,0 +1,3 @@
+export default function LoginPage() {
+  return <div>Login</div>;
+}

client/src/pages/RegisterPage.tsx

@@ -0,0 +1,3 @@
+export default function RegisterPage() {
+  return <div>Register</div>;
+}