fix(stats): review fuzzy AniList duplicates before merging

- Preserve merged title aliases for future episodes
- Fail closed when queued writes cannot drain

stats/src/hooks/useModalFocus.ts

@@ -0,0 +1,73 @@
+import { useEffect, useRef, type RefObject } from 'react';
+
+const FOCUSABLE_SELECTOR = [
+  'button:not([disabled])',
+  'input:not([disabled])',
+  'select:not([disabled])',
+  'textarea:not([disabled])',
+  'a[href]',
+  '[tabindex]:not([tabindex="-1"])',
+].join(',');
+
+interface UseModalFocusOptions {
+  dialogRef: RefObject<HTMLElement | null>;
+  initialFocusRef: RefObject<HTMLElement | null>;
+  dismissDisabled?: boolean;
+  onDismiss: () => void;
+}
+
+export function useModalFocus({
+  dialogRef,
+  initialFocusRef,
+  dismissDisabled = false,
+  onDismiss,
+}: UseModalFocusOptions): void {
+  const dismissDisabledRef = useRef(dismissDisabled);
+  const onDismissRef = useRef(onDismiss);
+  dismissDisabledRef.current = dismissDisabled;
+  onDismissRef.current = onDismiss;
+
+  useEffect(() => {
+    const previouslyFocused =
+      document.activeElement instanceof HTMLElement ? document.activeElement : null;
+    initialFocusRef.current?.focus();
+
+    const handleKeyDown = (event: KeyboardEvent) => {
+      if (event.key === 'Escape') {
+        if (!dismissDisabledRef.current) {
+          event.preventDefault();
+          onDismissRef.current();
+        }
+        return;
+      }
+      if (event.key !== 'Tab') return;
+
+      const dialog = dialogRef.current;
+      if (!dialog) return;
+      const focusable = [...dialog.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR)];
+      const first = focusable[0];
+      const last = focusable.at(-1);
+      if (!first || !last) return;
+
+      if (
+        event.shiftKey &&
+        (document.activeElement === first || !dialog.contains(document.activeElement))
+      ) {
+        event.preventDefault();
+        last.focus();
+      } else if (
+        !event.shiftKey &&
+        (document.activeElement === last || !dialog.contains(document.activeElement))
+      ) {
+        event.preventDefault();
+        first.focus();
+      }
+    };
+
+    document.addEventListener('keydown', handleKeyDown);
+    return () => {
+      document.removeEventListener('keydown', handleKeyDown);
+      previouslyFocused?.focus();
+    };
+  }, [dialogRef, initialFocusRef]);
+}