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/components/ErrorBoundary.tsx

@@ -0,0 +1,45 @@
+"use client";
+
+import { Component, ReactNode } from "react";
+
+type Props = {
+  fallback?: ReactNode;
+  children: ReactNode;
+};
+
+type State = {
+  hasError: boolean;
+  error: Error | null;
+};
+
+export class ErrorBoundary extends Component<Props, State> {
+  constructor(props: Props) {
+    super(props);
+    this.state = { hasError: false, error: null };
+  }
+
+  static getDerivedStateFromError(error: Error): State {
+    return { hasError: true, error };
+  }
+
+  render() {
+    if (this.state.hasError) {
+      return (
+        this.props.fallback ?? (
+          <div className="flex min-h-[200px] items-center justify-center rounded-lg border border-red-200 bg-red-50 p-6 text-center">
+            <div>
+              <p className="mb-2 font-semibold text-red-700">
+                Something went wrong
+              </p>
+              <p className="text-sm text-red-600">
+                Please refresh the page or try again later
+              </p>
+            </div>
+          </div>
+        )
+      );
+    }
+
+    return this.props.children;
+  }
+}