Handle composition input in PDF text editor (#5192)

## Summary
- track IME composition state in the PDF text editor to avoid
interrupting phonetic input methods
- update text syncing to occur after composition completes and skip
redundant updates mid-composition

## Testing
- npm run lint -- --max-warnings 0


------
[Codex
Task](https://chatgpt.com/codex/tasks/task_b_693744be74148328bd3bda9150de6e56)

build.gradle

@@ -57,7 +57,7 @@ repositories {
 
 allprojects {
     group = 'stirling.software'
-    version = '2.1.1'
+    version = '2.1.2'
 
     configurations.configureEach {
         exclude group: 'commons-logging', module: 'commons-logging'

frontend/src/core/components/tools/pdfTextEditor/PdfTextEditorView.tsx

@@ -334,6 +334,7 @@ const PdfTextEditorView = ({ data }: PdfTextEditorViewProps) => {
   const containerRef = useRef<HTMLDivElement | null>(null);
   const editorRefs = useRef<Map<string, HTMLDivElement>>(new Map());
   const caretOffsetsRef = useRef<Map<string, number>>(new Map());
+  const composingGroupsRef = useRef<Set<string>>(new Set());
   const lastSelectedGroupIdRef = useRef<string | null>(null);
   const widthOverridesRef = useRef<Map<string, number>>(widthOverrides);
   const resizingRef = useRef<{
@@ -614,6 +615,18 @@ const PdfTextEditorView = ({ data }: PdfTextEditorViewProps) => {
     [editingGroupId, onGroupEdit],
   );
 
+  const handleCompositionStart = useCallback((groupId: string) => {
+    composingGroupsRef.current.add(groupId);
+  }, []);
+
+  const handleCompositionEnd = useCallback(
+    (element: HTMLElement, pageIndex: number, groupId: string) => {
+      composingGroupsRef.current.delete(groupId);
+      syncEditorValue(element, pageIndex, groupId);
+    },
+    [syncEditorValue],
+  );
+
   const handleMergeSelection = useCallback(() => {
     if (!canMergeSelection) {
       return;
@@ -2279,6 +2292,10 @@ const selectionToolbarPosition = useMemo(() => {
                                 contentEditable
                                 suppressContentEditableWarning
                                 data-editor-group={group.id}
+                                onCompositionStart={() => handleCompositionStart(group.id)}
+                                onCompositionEnd={(event) =>
+                                  handleCompositionEnd(event.currentTarget, group.pageIndex, group.id)
+                                }
                                 onFocus={(event) => {
                                   const primaryFont = fontFamily.split(',')[0]?.replace(/['"]/g, '').trim();
                                   if (primaryFont && typeof document !== 'undefined') {
@@ -2300,6 +2317,7 @@ const selectionToolbarPosition = useMemo(() => {
                                   event.stopPropagation();
                                 }}
                                 onBlur={(event) => {
+                                  composingGroupsRef.current.delete(group.id);
                                   syncEditorValue(event.currentTarget, group.pageIndex, group.id, {
                                     skipCaretRestore: true,
                                   });
@@ -2309,6 +2327,9 @@ const selectionToolbarPosition = useMemo(() => {
                                   setEditingGroupId(null);
                                 }}
                                 onInput={(event) => {
+                                  if (composingGroupsRef.current.has(group.id)) {
+                                    return;
+                                  }
                                   syncEditorValue(event.currentTarget, group.pageIndex, group.id);
                                 }}
                                 style={{