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/utils/ripgrep.ts

@@ -4,9 +4,9 @@ import memoize from 'lodash-es/memoize.js'
 import { homedir } from 'os'
 import * as path from 'path'
 import { logEvent } from 'src/services/analytics/index.js'
-import { fileURLToPath } from 'url'
 import { isInBundledMode } from './bundledMode.js'
 import { logForDebugging } from './debug.js'
+import { distRoot } from './distRoot.js'
 import { isEnvDefinedFalsy } from './envUtils.js'
 import { execFileNoThrow } from './execFileNoThrow.js'
 import { findExecutable } from './findExecutable.js'
@@ -14,25 +14,9 @@ import { logError } from './log.js'
 import { getPlatform } from './platform.js'
 import { countCharInString } from './stringUtils.js'
 
-const __filename = fileURLToPath(import.meta.url)
-// we use node:path.join instead of node:url.resolve because the former doesn't encode spaces
-// In dev mode: __filename = <root>/src/utils/ripgrep.ts → __dirname = <root>/src/utils/
-// In built mode (bun): __filename = <root>/dist/chunk-xxx.js → need <root>/dist/
-// In built mode (vite): __filename = <root>/dist/chunks/chunk-xxx.js → need <root>/dist/
-// Both built modes: the dist root is at <root>/dist/ where dist/vendor/ripgrep/ lives.
 const __dirname = (() => {
-  const dir = path.dirname(__filename)
-  // Test mode: from src/utils/ → project root
-  if (process.env.NODE_ENV === 'test') return path.resolve(dir, '../../../')
-  // Check if we're inside a dist directory at any depth
-  // (dist/ or dist/chunks/) — vendor lives at <dist-root>/vendor/ripgrep/
-  const parts = dir.split(path.sep)
-  const distIdx = parts.lastIndexOf('dist')
-  if (distIdx !== -1) {
-    return parts.slice(0, distIdx + 1).join(path.sep)
-  }
-  // Dev mode: from src/utils/ → src/utils/
-  return dir
+  if (process.env.NODE_ENV === 'test') return path.resolve(distRoot)
+  return distRoot
 })()
 
 type RipgrepConfig = {