Add edit table of contents tool to React UI (#4917)

## Summary
- add a dedicated edit table of contents tool to the React UI, complete
with bookmark editor, import/export actions, and parameter handling
- register the tool in the translated registry and extend the English
translations with the new strings
- wire up the backend endpoints through a new operation hook and
form-data serialization helpers

## Testing
- ./gradlew build

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[Codex
Task](https://chatgpt.com/codex/tasks/task_b_691a4a87a9c4832899ecd1c55989f27f)

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Co-authored-by: Reece Browne <74901996+reecebrowne@users.noreply.github.com>

frontend/src/core/utils/editTableOfContents.ts

@@ -0,0 +1,47 @@
+export interface BookmarkPayload {
+  title: string;
+  pageNumber: number;
+  children?: BookmarkPayload[];
+}
+
+export interface BookmarkNode {
+  id: string;
+  title: string;
+  pageNumber: number;
+  children: BookmarkNode[];
+  expanded: boolean;
+}
+
+const createBookmarkId = () => {
+  if (typeof crypto !== 'undefined' && 'randomUUID' in crypto) {
+    return crypto.randomUUID();
+  }
+
+  return `bookmark-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
+};
+
+export const createBookmarkNode = (bookmark?: Partial<BookmarkNode>): BookmarkNode => ({
+  id: bookmark?.id ?? createBookmarkId(),
+  title: bookmark?.title ?? '',
+  pageNumber: bookmark?.pageNumber ?? 1,
+  children: bookmark?.children ? bookmark.children.map(child => createBookmarkNode(child)) : [],
+  expanded: bookmark?.expanded ?? true,
+});
+
+export const hydrateBookmarkPayload = (payload: BookmarkPayload[] = []): BookmarkNode[] => {
+  return payload.map(item => ({
+    id: createBookmarkId(),
+    title: item.title ?? '',
+    pageNumber: typeof item.pageNumber === 'number' && item.pageNumber > 0 ? item.pageNumber : 1,
+    expanded: true,
+    children: item.children ? hydrateBookmarkPayload(item.children) : [],
+  }));
+};
+
+export const serializeBookmarkNodes = (bookmarks: BookmarkNode[]): BookmarkPayload[] => {
+  return bookmarks.map(bookmark => ({
+    title: bookmark.title,
+    pageNumber: bookmark.pageNumber,
+    children: serializeBookmarkNodes(bookmark.children),
+  }));
+};