feat: add "My Datasets" page

frontend/src/components/AppLayout.tsx

@@ -34,6 +34,9 @@ const AppLayout = () => {
   const navigate = useNavigate();
   const [isSignedIn, setIsSignedIn] = useState(false);
   const [currentUser, setCurrentUser] = useState<Record<string, unknown> | null>(null);
+  const [lastDatasetId, setLastDatasetId] = useState<string | null>(
+    localStorage.getItem("last_dataset_id")
+  );
 
   const syncAuthState = useCallback(async () => {
     const token = localStorage.getItem("access_token");
@@ -63,6 +66,17 @@ const AppLayout = () => {
     void syncAuthState();
   }, [location.pathname, syncAuthState]);
 
+  useEffect(() => {
+    const datasetMatch = location.pathname.match(/^\/dataset\/(\d+)\/(status|stats)$/);
+    if (!datasetMatch) {
+      return;
+    }
+
+    const datasetId = datasetMatch[1];
+    localStorage.setItem("last_dataset_id", datasetId);
+    setLastDatasetId(datasetId);
+  }, [location.pathname]);
+
   const onAuthButtonClick = () => {
     if (isSignedIn) {
       localStorage.removeItem("access_token");
@@ -107,6 +121,31 @@ const AppLayout = () => {
           </div>
 
           <div style={{ ...styles.controls, flexWrap: "wrap" }}>
+            <button
+              type="button"
+              style={location.pathname === "/upload" ? styles.buttonPrimary : styles.buttonSecondary}
+              onClick={() => navigate("/upload")}
+            >
+              Upload
+            </button>
+
+            <button
+              type="button"
+              style={location.pathname === "/datasets" ? styles.buttonPrimary : styles.buttonSecondary}
+              onClick={() => navigate("/datasets")}
+            >
+              My datasets
+            </button>
+
+            <button
+              type="button"
+              style={location.pathname.endsWith("/stats") ? styles.buttonPrimary : styles.buttonSecondary}
+              onClick={() => lastDatasetId && navigate(`/dataset/${lastDatasetId}/stats`)}
+              disabled={!lastDatasetId}
+            >
+              {lastDatasetId ? "Last stats" : "Last stats (none)"}
+            </button>
+
             <button
               type="button"
               style={isSignedIn ? styles.buttonSecondary : styles.buttonPrimary}