perf: Vite 构建启用 code splitting，Bun RSS 从 966MB 降至 35MB

Bun/JSC 全量解析单文件大 JS 的 bytecode 和 JIT，17MB 产物导致
RSS 暴涨至 ~1GB（Node/V8 懒解析仅需 ~220MB）。启用代码分割后
Bun 按需加载 chunk，--version RSS 35MB，完整加载 ~500MB。

改动：
- vite.config.ts: 移除 codeSplitting:false，添加 chunkFileNames
- post-build.ts: 遍历 dist/ + dist/chunks/ 所有文件做 Bun patch
- 新建 distRoot.ts 共享工具函数，统一路径定位逻辑
- ripgrep.ts/computerUse/setup.ts/claudeInChrome/setup.ts/updateCCB.ts:
  用 distRoot 替换内联 import.meta.url 路径推算

src/cli/updateCCB.ts

@@ -9,9 +9,9 @@ import chalk from 'chalk'
 import { execSync } from 'node:child_process'
 import { existsSync, readFileSync } from 'node:fs'
 import { homedir } from 'node:os'
-import { join, dirname } from 'node:path'
-import { fileURLToPath } from 'node:url'
+import { join } from 'node:path'
 import { logForDebugging } from '../utils/debug.js'
+import { distRoot } from '../utils/distRoot.js'
 import { execFileNoThrowWithCwd } from '../utils/execFileNoThrow.js'
 import { gracefulShutdown } from '../utils/gracefulShutdown.js'
 import { writeToStdout } from '../utils/process.js'
@@ -19,12 +19,9 @@ import { writeToStdout } from '../utils/process.js'
 const PACKAGE_NAME = 'claude-code-best'
 
 function getCurrentVersion(): string {
-  // Read version from the nearest package.json (walks up from this file)
+  // Read version from the nearest package.json (walks up from dist root)
   try {
-    const __dirname = dirname(fileURLToPath(import.meta.url))
-    // In dev: src/cli/updateCCB.ts → ../../package.json
-    // In build: dist/chunks/xxx.js → ../../package.json (may not exist)
-    const pkgPath = join(__dirname, '..', '..', 'package.json')
+    const pkgPath = join(distRoot, '..', 'package.json')
     if (existsSync(pkgPath)) {
       const pkg = JSON.parse(readFileSync(pkgPath, 'utf-8'))
       if (pkg.version) return pkg.version