feat(web): Phase 3a — migrate CRA to Vite + make the app runnable

The frontend was a Create React App scaffold (deprecated) where App.tsx was
still the stock 'Learn React' boilerplate — the implemented login/register pages
and stores were never mounted (no router). This swaps to Vite/TS5, fixes the
broken API client, wires a real router + dashboard, and lands on a runnable app.

Tooling swap (CRA -> Vite):
* Dropped react-scripts, web-vitals, @types/jest; added vite 6 + @vitejs/plugin-react
  + vitest 3 + jsdom; bumped typescript 4.9 -> 5.6, @types/node 16 -> 22.
* New vite.config.ts (with dev-server /api proxy -> backend, no CORS in dev),
  tsconfig.json (target es2022, moduleResolution bundler, vite/client types),
  tsconfig.node.json, vite-env.d.ts, root index.html.
* .env / .env.example (VITE_API_URL + VITE_API_TARGET). Renamed index.tsx ->
  main.tsx (theme provider + CssBaseline). Deleted all CRA boilerplate
  (App.css, logo.svg, App.test.tsx, reportWebVitals.ts, react-app-env.d.ts,
  CRA index.html/logos/readme) + the orphaned empty web/src/ and mobile/ trees.
* node_modules 479MB -> 265MB; lockfile 695KB -> 198KB.

API client correctness (services/api.ts):
* Env var process.env.REACT_APP_* -> import.meta.env.VITE_*; dropped the
  hardcoded http://solaria:8001/api (now /api via the dev proxy).
* Fixed contract mismatches: getCurrentUser /auth/me -> /users/me;
  updateMedication PUT -> POST /:id; deleteMedication DELETE -> POST /:id/delete.
* Added refreshToken() (/auth/refresh) and server-side logout() (/auth/logout).
* Removed the /lab-results block (no backend route).
* 401 interceptor now attempts ONE silent refresh (deduped) before bouncing to
  /login, instead of hard-redirecting on every 401.
* CreateMedicationRequest type now matches the backend (required route +
  profile_id fields).

Router + dashboard:
* Real App.tsx with BrowserRouter: /login, /register (public), / (protected
  Dashboard), catch-all -> /.
* New Dashboard.tsx: MUI AppBar + welcome card, loads the current user on mount,
  logout button. The shell feature UIs get built into next.
* LoginPage/RegisterPage navigate to / (was /dashboard); store logout is now
  async; AuthTokens type includes refresh_token.
* Minimal MUI theme.ts.

Verified: npm run build clean (TS5 strict + Vite), dev server serves the app +
proxies /api to the backend, vitest runs. Solaria round-trip confirmed all
corrected endpoints (/users/me 200, /auth/refresh 200, /auth/logout 204,
medication create 200).

web/normogen-web/src/pages/Dashboard.tsx

@@ -0,0 +1,70 @@
+import { useEffect, type FC } from 'react';
+import { useNavigate } from 'react-router-dom';
+import {
+  AppBar,
+  Toolbar,
+  Typography,
+  Button,
+  Container,
+  Card,
+  CardContent,
+  Box,
+  CircularProgress,
+} from '@mui/material';
+import { useAuthStore } from '../store/useStore';
+
+export const Dashboard: FC = () => {
+  const navigate = useNavigate();
+  const { user, isAuthenticated, isLoading, loadUser, logout } = useAuthStore();
+
+  // On mount, refresh the user record from the backend (confirms the token is
+  // still valid and pulls the latest profile).
+  useEffect(() => {
+    if (isAuthenticated && !user) {
+      loadUser();
+    }
+  }, [isAuthenticated, user, loadUser]);
+
+  const handleLogout = async () => {
+    await logout();
+    navigate('/login', { replace: true });
+  };
+
+  return (
+    <>
+      <AppBar position="static">
+        <Toolbar>
+          <Typography variant="h6" component="div" sx={{ flexGrow: 1 }}>
+            Normogen
+          </Typography>
+          <Button color="inherit" onClick={handleLogout}>
+            Logout
+          </Button>
+        </Toolbar>
+      </AppBar>
+
+      <Container maxWidth="md" sx={{ mt: 4 }}>
+        {isLoading && (
+          <Box display="flex" justifyContent="center" mt={4}>
+            <CircularProgress />
+          </Box>
+        )}
+
+        <Card>
+          <CardContent>
+            <Typography variant="h5" gutterBottom>
+              Welcome{user ? `, ${user.username}` : ''}
+            </Typography>
+            <Typography variant="body1" color="text.secondary">
+              You&apos;re signed in to Normogen.
+            </Typography>
+            <Typography variant="body2" color="text.secondary" sx={{ mt: 2 }}>
+              This is the dashboard shell. Medication management, health statistics,
+              and drug-interaction checking UIs will be built here.
+            </Typography>
+          </CardContent>
+        </Card>
+      </Container>
+    </>
+  );
+};

web/normogen-web/src/pages/LoginPage.tsx

@@ -24,7 +24,7 @@ export const LoginPage: React.FC = () => {
     
     try {
       await login(email, password);
-      navigate('/dashboard');
+      navigate('/');
     } catch (err) {
       // Error is handled by the store
     }

web/normogen-web/src/pages/RegisterPage.tsx

@@ -38,7 +38,7 @@ export const RegisterPage: React.FC = () => {
     
     try {
       await register(username, email, password);
-      navigate('/dashboard');
+      navigate('/');
     } catch (err) {
       // Error is handled by the store
     }