feat: add filter bar component with multi-select dropdowns

Implement a new filter bar component that allows users to filter data
by date range, username, models, and organizations. The filter bar
includes a multi-select dropdown for models and organizations,
enhancing user experience by providing a more interactive way to
manage filters. Additionally, integrate loading state in the app
component to improve data fetching feedback.

Author: congiuluc

src/App.tsx

@@ -131,7 +131,7 @@ function Dashboard({
 }
 
 export default function App() {
-  const { data, saveData, clearData } = useSessionData();
+  const { data, saveData, clearData, loading } = useSessionData();
 
   const usernames = useMemo(() => {
     if (!data) return [];
@@ -140,6 +140,14 @@ export default function App() {
 
   const { profiles, loading: profilesLoading, resolve } = useGitHubProfiles(usernames);
 
+  if (loading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center p-4">
+        <div className="animate-pulse-soft text-muted-foreground text-sm">Loading data…</div>
+      </div>
+    );
+  }
+
   if (!data) {
     return (
       <div className="min-h-screen flex items-center justify-center p-4">