task-11: complete QA + hardening with resilience fixes

- Created comprehensive QA checklist covering edge cases (missing EXIF, timezones, codecs, corrupt files)
- Added ErrorBoundary component wrapped around TimelineTree and MediaPanel
- Created global error.tsx page for unhandled errors
- Improved failed asset UX with red borders, warning icons, and inline error display
- Added loading skeletons to TimelineTree and MediaPanel
- Added retry button for failed media loads
- Created DEPLOYMENT_VALIDATION.md with validation commands and checklist
- Applied k8s recommendations:
  - Changed node affinity to required for compute nodes (Pi 5)
  - Enabled Tailscale LoadBalancer service for MinIO S3 (reliable Range requests)
  - Enabled cleanup CronJob for staging files

apps/web/app/error.tsx

@@ -0,0 +1,35 @@
+"use client";
+
+import { useEffect } from "react";
+
+export default function Error({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  useEffect(() => {
+    console.error("Application error:", error);
+  }, [error]);
+
+  return (
+    <main className="flex min-h-screen items-center justify-center p-6">
+      <div className="max-w-md rounded-lg border border-red-200 bg-red-50 p-8 text-center">
+        <h1 className="mb-4 text-xl font-semibold text-red-700">
+          Something went wrong
+        </h1>
+        <p className="mb-6 text-sm text-red-600">
+          An unexpected error occurred. Please try refreshing the page.
+        </p>
+        <button
+          type="button"
+          onClick={reset}
+          className="rounded bg-red-600 px-4 py-2 text-white transition hover:bg-red-700"
+        >
+          Refresh
+        </button>
+      </div>
+    </main>
+  );
+}