feat: restructure styles and components for improved design system

- Added typography and design system styles to globals.css.
- Removed deprecated home.css and landing.css files.
- Introduced DiscordSignInButton component for Discord authentication.
- Created Card and CardGrid components for structured content display.
- Implemented ContainerShowcase to demonstrate card usage and layout.
- Added DesignSystemTabs for navigation between design system sections.
- Established typography.css for consistent text styling across components.
- Added tests for typography styles to ensure compliance with design standards.

src/App.tsx

@@ -1,57 +1,11 @@
-import { Route, Routes, useLocation, useNavigate } from "react-router";
-import { AuthControls } from "./components/AuthControls";
-import { Home } from "./pages/Home";
-import { About } from "./pages/About";
-import { Settings } from "./pages/Settings";
+import { Navigate, Route, Routes } from "react-router";
 import { DesignSystem } from "./pages/DesignSystem";
-import { AuthProvider, useAuth } from "./components/AuthProvider";
-import { Landing } from "./pages/Landing";
-import { Button } from "./components/design-system/primitives";
 
 export function App() {
-  const { pathname } = useLocation();
-  if (pathname === "/design-system" || pathname === "/design-system/") return <DesignSystem />;
-  return <AuthProvider><AppRoutes /></AuthProvider>;
-}
-
-function AppRoutes() {
-  const navigate = useNavigate();
-  const { pathname } = useLocation();
-  const { user, loading, accountError, retry } = useAuth();
-
-  if (pathname === "/") {
-    if (loading || accountError) return (
-      <div className="ds-root landing-root">
-        <main className="landing-account-state">
-          <a className="ds-wordmark" href="/">minabot.</a>
-          {loading ? <p role="status">Loading your account…</p> : <>
-            <p role="alert">{accountError}</p>
-            <Button variant="secondary" onClick={retry}>Try again</Button>
-          </>}
-        </main>
-      </div>
-    );
-    if (!user) return <Landing />;
-    return <Home />;
-  }
-
   return (
-    <>
-      <nav aria-label="Main navigation">
-        <button type="button" disabled={pathname === "/"} onClick={() => navigate("/")}>Home</button>{" "}
-        <button type="button" disabled={pathname === "/about"} onClick={() => navigate("/about")}>About</button>{" "}
-        <button type="button" disabled={pathname === "/settings"} onClick={() => navigate("/settings")}>Settings</button>
-        {" "}<button type="button" onClick={() => navigate("/design-system")}>Design system</button>
-      </nav>
-      <AuthControls />
-      <main>
-        <Routes>
-          <Route path="/" element={<Home />} />
-          <Route path="/about" element={<About />} />
-          <Route path="/settings" element={<Settings />} />
-          <Route path="*" element={<h1>Page not found</h1>} />
-        </Routes>
-      </main>
-    </>
+    <Routes>
+      <Route path="/design-system" element={<DesignSystem />} />
+      <Route path="*" element={<Navigate to="/design-system" replace />} />
+    </Routes>
   );
 }