fix: 恢复消息流中 diff 高亮渲染功能

还原 commit 51b8ad46 删除的 diff highlight 显示：FileEdit/FileWrite 工具
执行成功后重新展示 StructuredDiffList，拒绝时重新展示高亮代码预览或
带上下文的 diff 视图。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packages/builtin-tools/src/tools/FileWriteTool/UI.tsx

@@ -1,6 +1,8 @@
 import type { ToolResultBlockParam } from '@anthropic-ai/sdk/resources/index.mjs';
-import { relative } from 'path';
+import type { StructuredPatchHunk } from 'diff';
+import { isAbsolute, relative, resolve } from 'path';
 import * as React from 'react';
+import { Suspense, use, useState } from 'react';
 import { MessageResponse } from 'src/components/MessageResponse.js';
 import { extractTag } from 'src/utils/messages.js';
 import { CtrlOToExpand } from 'src/components/CtrlOToExpand.js';
@@ -15,8 +17,11 @@ import { FilePathLink } from 'src/components/FilePathLink.js';
 import type { ToolProgressData } from 'src/Tool.js';
 import type { ProgressMessage } from 'src/types/message.js';
 import { getCwd } from 'src/utils/cwd.js';
+import { getPatchForDisplay } from 'src/utils/diff.js';
 import { getDisplayPath } from 'src/utils/file.js';
+import { logError } from 'src/utils/log.js';
 import { getPlansDirectory } from 'src/utils/plans.js';
+import { openForScan, readCapped } from 'src/utils/readEditContext.js';
 import type { Output } from './FileWriteTool.js';
 
 const MAX_LINES_TO_RENDER = 10;
@@ -122,10 +127,115 @@ export function renderToolUseMessage(
 }
 
 export function renderToolUseRejectedMessage(
-  { file_path }: { file_path: string; content: string },
+  { file_path, content }: { file_path: string; content: string },
   { style, verbose }: { style?: 'condensed'; verbose: boolean },
 ): React.ReactNode {
-  return <FileEditToolUseRejectedMessage file_path={file_path} operation="write" style={style} verbose={verbose} />;
+  return <WriteRejectionDiff filePath={file_path} content={content} style={style} verbose={verbose} />;
+}
+
+type RejectionDiffData =
+  | { type: 'create' }
+  | { type: 'update'; patch: StructuredPatchHunk[]; oldContent: string }
+  | { type: 'error' };
+
+function WriteRejectionDiff({
+  filePath,
+  content,
+  style,
+  verbose,
+}: {
+  filePath: string;
+  content: string;
+  style?: 'condensed';
+  verbose: boolean;
+}): React.ReactNode {
+  const [dataPromise] = useState(() => loadRejectionDiff(filePath, content));
+  const firstLine = content.split('\n')[0] ?? null;
+  const createFallback = (
+    <FileEditToolUseRejectedMessage
+      file_path={filePath}
+      operation="write"
+      content={content}
+      firstLine={firstLine}
+      verbose={verbose}
+    />
+  );
+  return (
+    <Suspense fallback={createFallback}>
+      <WriteRejectionBody
+        promise={dataPromise}
+        filePath={filePath}
+        firstLine={firstLine}
+        createFallback={createFallback}
+        style={style}
+        verbose={verbose}
+      />
+    </Suspense>
+  );
+}
+
+function WriteRejectionBody({
+  promise,
+  filePath,
+  firstLine,
+  createFallback,
+  style,
+  verbose,
+}: {
+  promise: Promise<RejectionDiffData>;
+  filePath: string;
+  firstLine: string | null;
+  createFallback: React.ReactNode;
+  style?: 'condensed';
+  verbose: boolean;
+}): React.ReactNode {
+  const data = use(promise);
+  if (data.type === 'create') return createFallback;
+  if (data.type === 'error') {
+    return (
+      <MessageResponse>
+        <Text>(No changes)</Text>
+      </MessageResponse>
+    );
+  }
+  return (
+    <FileEditToolUseRejectedMessage
+      file_path={filePath}
+      operation="update"
+      patch={data.patch}
+      firstLine={firstLine}
+      fileContent={data.oldContent}
+      style={style}
+      verbose={verbose}
+    />
+  );
+}
+
+async function loadRejectionDiff(filePath: string, content: string): Promise<RejectionDiffData> {
+  try {
+    const fullFilePath = isAbsolute(filePath) ? filePath : resolve(getCwd(), filePath);
+    const handle = await openForScan(fullFilePath);
+    if (handle === null) return { type: 'create' };
+    let oldContent: string | null;
+    try {
+      oldContent = await readCapped(handle);
+    } finally {
+      await handle.close();
+    }
+    // File exceeds MAX_SCAN_BYTES — fall back to the create view rather than
+    // OOMing on a diff of a multi-GB file.
+    if (oldContent === null) return { type: 'create' };
+    const patch = getPatchForDisplay({
+      filePath,
+      fileContents: oldContent,
+      edits: [{ old_string: oldContent, new_string: content, replace_all: false }],
+    });
+    return { type: 'update', patch, oldContent };
+  } catch (e) {
+    // User may have manually applied the change while the diff was shown.
+    logError(e as Error);
+    return { type: 'error' };
+  }
 }
 
 export function renderToolUseErrorMessage(
@@ -179,6 +289,8 @@ export function renderToolResultMessage(
         <FileEditToolUpdatedMessage
           filePath={filePath}
           structuredPatch={structuredPatch}
+          firstLine={content.split('\n')[0] ?? null}
+          fileContent={originalFile ?? undefined}
           style={style}
           verbose={verbose}
           previewHint={isPlanFile ? '/plan to preview' : undefined}