fix: 优化内存峰值与 CPU 性能，降低 100-300MB 内存占用

- claude.ts: 流式字符串拼接从 O(n²) += 改为数组累积 join，消除 4 处热点
- Messages.tsx: 合并 3 组独立遍历为单次 pass（thinking/bash 查找、3-filter 链、divider/selectedIdx）
- HighlightedCode.tsx: ColorFile 实例添加模块级 LRU 缓存（50 条），避免重复创建
- screen.ts: StylePool 衍生缓存添加 1000 条上限淘汰，防止无界增长
- CompanionSprite.tsx: TICK_MS 从 500ms 提升至 1000ms，减少 setState 频率
- connection.ts: MCP stderr 缓冲从 64MB 降至 8MB
- stringUtils.ts: MAX_STRING_LENGTH 从 32MB 降至 2MB
- sessionStorage.ts: Transcript 写入队列添加 1000 条上限
- query.ts: spread 改 concat 减少一次数组拷贝
- PromptInputFooterLeftSide.tsx: 显示进程 pid 便于调试

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

packages/@ant/ink/src/core/screen.ts

@@ -119,6 +119,44 @@ export class StylePool {
     this.none = this.intern([])
   }
 
+  private static readonly CACHE_MAX = 1000
+
+  /**
+   * Evict oldest entries from derivative caches when they exceed the limit.
+   * ids/styles are never evicted (id is an array index).
+   */
+  private evictCacheIfNeeded(): void {
+    if (this.transitionCache.size > StylePool.CACHE_MAX) {
+      const keys = this.transitionCache.keys()
+      for (
+        let i = 0;
+        i < this.transitionCache.size - StylePool.CACHE_MAX;
+        i++
+      ) {
+        const k = keys.next().value
+        if (k !== undefined) this.transitionCache.delete(k)
+      }
+    }
+    if (this.inverseCache.size > StylePool.CACHE_MAX) {
+      const keys = this.inverseCache.keys()
+      for (let i = 0; i < this.inverseCache.size - StylePool.CACHE_MAX; i++) {
+        const k = keys.next().value
+        if (k !== undefined) this.inverseCache.delete(k)
+      }
+    }
+    if (this.currentMatchCache.size > StylePool.CACHE_MAX) {
+      const keys = this.currentMatchCache.keys()
+      for (
+        let i = 0;
+        i < this.currentMatchCache.size - StylePool.CACHE_MAX;
+        i++
+      ) {
+        const k = keys.next().value
+        if (k !== undefined) this.currentMatchCache.delete(k)
+      }
+    }
+  }
+
   /**
    * Intern a style and return its ID. Bit 0 of the ID encodes whether the
    * style has a visible effect on space characters (background, inverse,
@@ -136,6 +174,7 @@ export class StylePool {
         (rawId << 1) |
         (styles.length > 0 && hasVisibleSpaceEffect(styles) ? 1 : 0)
       this.ids.set(key, id)
+      this.evictCacheIfNeeded()
     }
     return id
   }

packages/mcp-client/src/connection.ts

@@ -114,7 +114,7 @@ export async function withConnectionTimeout<T>(
  */
 export function captureStderr(
   transport: StdioClientTransport,
-  maxSize = 64 * 1024 * 1024,
+  maxSize = 8 * 1024 * 1024,
 ): {
   getOutput: () => string
   clearOutput: () => void