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>

src/buddy/CompanionSprite.tsx

@@ -12,9 +12,9 @@ import { getCompanion } from './companion.js';
 import { renderFace, renderSprite, spriteFrameCount } from './sprites.js';
 import { RARITY_COLORS } from './types.js';
 
-const TICK_MS = 500;
-const BUBBLE_SHOW = 20; // ticks → ~10s at 500ms
-const FADE_WINDOW = 6; // last ~3s the bubble dims so you know it's about to go
+const TICK_MS = 1000;
+const BUBBLE_SHOW = 10; // ticks → ~10s at 1000ms
+const FADE_WINDOW = 3; // last ~3s the bubble dims so you know it's about to go
 const PET_BURST_MS = 2500; // how long hearts float after /buddy pet
 
 // Idle sequence: mostly rest (frame 0), occasional fidget (frames 1-2), rare blink.