fix: prevent IME preedit overflow in mind map node editor (#14520)

## Summary

Update the edgeless shape text editor to resize mind map node text
bounds while IME composition is in progress.

## Changes

- listen to `compositionupdate` on the inline editor container
- trigger `_updateElementWH()` on `compositionupdate` and
`compositionend`
- keep text box dimensions in sync before composition is committed

## Testing

- Not run locally: `pnpm` is not available in this environment, so
package build/tests could not be executed here.

Fixes #11515


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Editor mounting tolerates missing/null elements and validates input to
avoid errors.
* Text creation/update consistently targets the refreshed element to
prevent mismatches.
* Inline editor listens for IME composition events and schedules
layout/size recalculation (with proper cleanup) so sizing stays in sync.

* **Tests**
* Added an integration test verifying layout/size updates during IME
composition events.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: DarkSky <25152247+darkskygit@users.noreply.github.com>
Co-authored-by: DarkSky <darksky2048@gmail.com>

blocksuite/affine/model/src/elements/mindmap/mindmap.ts

@@ -311,7 +311,6 @@ export class MindmapElementModel extends GfxGroupLikeElementModel<MindmapElement
         id = this.surface.addElement({
           type,
           xywh: '[0,0,100,30]',
-          maxWidth: false,
           ...props,
           ...style.node,
         });
@@ -345,7 +344,6 @@ export class MindmapElementModel extends GfxGroupLikeElementModel<MindmapElement
         id = this.surface.addElement({
           type,
           xywh: '[0,0,113,41]',
-          maxWidth: false,
           ...props,
           ...rootStyle,
         });
@@ -834,7 +832,12 @@ export class MindmapElementModel extends GfxGroupLikeElementModel<MindmapElement
     }
 
     const stashed = new Set<GfxPrimitiveElementModel>();
+    const stashedNodeIds = new Set<string>();
     const traverse = (node: MindmapNode) => {
+      if (this._stashedNode.has(node.id)) return;
+
+      this._stashedNode.add(node.id);
+      stashedNodeIds.add(node.id);
       node.element.stash('xywh');
       stashed.add(node.element);
 
@@ -846,7 +849,9 @@ export class MindmapElementModel extends GfxGroupLikeElementModel<MindmapElement
     traverse(mindNode);
 
     return () => {
-      this._stashedNode.delete(mindNode.id);
+      stashedNodeIds.forEach(id => {
+        this._stashedNode.delete(id);
+      });
       stashed.forEach(el => {
         el.pop('xywh');
       });

blocksuite/affine/model/src/elements/mindmap/style.ts

@@ -35,6 +35,7 @@ export type NodeStyle = {
   strokeColor: Color;
 
   textResizing: TextResizing;
+  maxWidth: false | number;
 
   fontSize: number;
   fontFamily: string;
@@ -62,6 +63,8 @@ export type ConnectorStyle = {
   mode: ConnectorMode;
 };
 
+export const MINDMAP_NODE_MAX_WIDTH = 512;
+
 export abstract class MindmapStyleGetter {
   abstract readonly root: NodeStyle;
 
@@ -90,6 +93,7 @@ export class StyleOne extends MindmapStyleGetter {
     radius: 8,
 
     textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+    maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
     strokeWidth: 4,
     strokeColor: '#53b2ef',
@@ -161,6 +165,7 @@ export class StyleOne extends MindmapStyleGetter {
         radius: 8,
 
         textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+        maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
         strokeWidth: 3,
         strokeColor: color,
@@ -198,6 +203,7 @@ export class StyleTwo extends MindmapStyleGetter {
     radius: 3,
 
     textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+    maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
     strokeWidth: 3,
     strokeColor: DefaultTheme.black,
@@ -271,6 +277,7 @@ export class StyleTwo extends MindmapStyleGetter {
         radius: 3,
 
         textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+        maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
         strokeWidth: 3,
         strokeColor: DefaultTheme.black,
@@ -308,6 +315,7 @@ export class StyleThree extends MindmapStyleGetter {
     radius: 10,
 
     textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+    maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
     strokeWidth: 0,
     strokeColor: 'transparent',
@@ -343,6 +351,7 @@ export class StyleThree extends MindmapStyleGetter {
         radius: 10,
 
         textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+        maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
         strokeWidth: 2,
         strokeColor,
@@ -420,6 +429,7 @@ export class StyleFour extends MindmapStyleGetter {
     radius: 0,
 
     textResizing: TextResizing.AUTO_WIDTH_AND_HEIGHT,
+    maxWidth: MINDMAP_NODE_MAX_WIDTH,
 
     strokeWidth: 0,
     strokeColor: 'transparent',