feat: Phase 7 - Frontend scaffolding and auth (T-023, T-024, T-025)

T-023: Initialize React project
- Vite + React 19 + TypeScript scaffold
- Tailwind CSS v4 with @tailwindcss/vite plugin
- Dependencies: react-router-dom, axios, @tanstack/react-query, lucide-react
- Project structure: api/, components/, pages/, context/, types/, hooks/, lib/

T-024: API client and auth context
- Axios client with JWT interceptor (auto-attach token, clear on 401)
- login() and getMe() API functions
- AuthContext: user state, login, logout, isAuthenticated, isLoading
- Token persistence via localStorage with hydration on mount
- TypeScript types for all backend models

T-025: Login page and layout
- LoginPage with form, error handling, redirect on success
- Layout with sidebar + header + Outlet
- Sidebar with role-aware navigation (System only for admin)
- ProtectedRoute wrapper with role-based access control
- Routes: /login, /dashboard, /techniques, /tests, /system

frontend/src/App.tsx

@@ -0,0 +1,41 @@
+import { Routes, Route, Navigate } from "react-router-dom";
+import LoginPage from "./pages/LoginPage";
+import DashboardPage from "./pages/DashboardPage";
+import TechniquesPage from "./pages/TechniquesPage";
+import TestsPage from "./pages/TestsPage";
+import SystemPage from "./pages/SystemPage";
+import Layout from "./components/Layout";
+import ProtectedRoute from "./components/ProtectedRoute";
+
+export default function App() {
+  return (
+    <Routes>
+      {/* Public */}
+      <Route path="/login" element={<LoginPage />} />
+
+      {/* Protected — wrapped in shared Layout */}
+      <Route
+        element={
+          <ProtectedRoute>
+            <Layout />
+          </ProtectedRoute>
+        }
+      >
+        <Route path="/dashboard" element={<DashboardPage />} />
+        <Route path="/techniques" element={<TechniquesPage />} />
+        <Route path="/tests" element={<TestsPage />} />
+        <Route
+          path="/system"
+          element={
+            <ProtectedRoute roles={["admin"]}>
+              <SystemPage />
+            </ProtectedRoute>
+          }
+        />
+      </Route>
+
+      {/* Catch-all → dashboard */}
+      <Route path="*" element={<Navigate to="/dashboard" replace />} />
+    </Routes>
+  );
+}