feat: first version of the interface, integrate Tailwind CSS and update routing

- Add Tailwind CSS dependencies and configure Vite to use Tailwind
- Implement routing with React Router for Landing and Dashboard pages
- Remove unused App.css file and refactor App component to utilize new structure
- Update global styles in index.css to incorporate Tailwind's utility classes

frontend/src/components/ui/Badge.jsx

@@ -0,0 +1,22 @@
+import {
+  DEFAULT_BADGE_CLASSES,
+  TYPE_BADGE_CLASSES,
+  TYPE_LABELS,
+} from "../../utils/publicationTypes";
+
+/**
+ * Pill-style badge that colour-codes a publication type (article, review, …).
+ * Falls back to the neutral palette for unknown types.
+ */
+export function Badge({ type }) {
+  const label = TYPE_LABELS[type] ?? type;
+  const classes = TYPE_BADGE_CLASSES[type] ?? DEFAULT_BADGE_CLASSES;
+
+  return (
+    <span
+      className={`inline-flex items-center whitespace-nowrap rounded-full px-2 py-0.5 text-[11px] font-medium tracking-wide ${classes}`}
+    >
+      {label}
+    </span>
+  );
+}