fix: 内存优化 — FileReadTool 100KB 上限、lookups 缓存、microcompact 替换清理

- FileReadTool maxResultSizeChars 从 Infinity 改为 100KB，大文件持久化到磁盘
- Messages.tsx 新增 computeMessageStructureKey 缓存，流式 delta 时跳过 8 个 Map/Set 重建
- microcompact 返回 clearedToolUseIds，query.ts 消费后清理 replacements Map 释放原始字符串
- 更新内存分析报告 Round 5 和 file-operations 文档

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

packages/builtin-tools/src/tools/FileReadTool/FileReadTool.ts

@@ -337,9 +337,10 @@ export type Output = z.infer<OutputSchema>
 export const FileReadTool = buildTool({
   name: FILE_READ_TOOL_NAME,
   searchHint: 'read files, images, PDFs, notebooks',
-  // Output is bounded by maxTokens (validateContentTokens). Persisting to a
-  // file the model reads back with Read is circular — never persist.
-  maxResultSizeChars: Infinity,
+  // Output is bounded by maxTokens (validateContentTokens). Results exceeding
+  // 100KB are persisted to disk (reducing memory pressure in long sessions)
+  // rather than kept in the message array indefinitely.
+  maxResultSizeChars: 100_000,
   strict: true,
   async description() {
     return DESCRIPTION