Load tool views on demand with isolated retry states

src/components/DeferredView.jsx

@@ -0,0 +1,22 @@
+import React, { Suspense, lazy, useMemo, useState } from 'react';
+
+class ViewErrorBoundary extends React.Component {
+  state = { failed: false };
+  static getDerivedStateFromError() { return { failed: true }; }
+  render() {
+    if (this.state.failed) return <div role="alert" className="p-4 border border-red-200 rounded-xl bg-red-50 text-red-900">
+      <p>Bu ekran yüklenemedi. Bağlantınızı kontrol edip yeniden deneyebilirsiniz.</p>
+      <button type="button" onClick={this.props.retry} className="mt-3 px-4 py-2 rounded-lg border border-red-300">Yeniden dene</button>
+    </div>;
+    return this.props.children;
+  }
+}
+
+/** Retry only this view; keep the application and saved work mounted. */
+export function DeferredView({ load }) {
+  const [attempt, setAttempt] = useState(0);
+  const View = useMemo(() => lazy(load), [load, attempt]);
+  return <ViewErrorBoundary key={attempt} retry={() => setAttempt(n => n + 1)}>
+    <Suspense fallback={<p role="status" className="p-4 text-slate-600">Ekran yükleniyor…</p>}><View /></Suspense>
+  </ViewErrorBoundary>;
+}