Fix/ripgrep fallback (#1273)

* fix: tmp 目录改用 os.tmpdir() + ripgrep 缺失时自动 fallback 系统 rg

1. Shell.ts / imagePaste.ts / filesystem.ts: Linux/macOS 默认 tmp 路径
   从硬编码 '/tmp' 改为 os.tmpdir()，自动适配 Termux/Android 等无 /tmp
   的环境；macOS 桌面零变化；CLAUDE_CODE_TMPDIR 仍优先级最高。

2. ripgrep.ts: builtin rg 二进制缺失时（Android/Termux、不完整安装）
   自动 fallback 到 PATH 上的系统 rg，通过 note 字段携带人读提示；
   /doctor 渲染 note；init 启动时写一行 stderr warning。

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

* fix: review fix — ripgrep note 文案修正 + init catch 加调试日志

- ripgrep "no ripgrep available" note 去掉无意义的 USE_BUILTIN_RIPGREP=0 建议
- init.ts ripgrep status check 的空 catch 加 logForDebugging

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

---------

Co-authored-by: glm-5.2 <zai-org@claude-code-best.win>

src/utils/permissions/filesystem.ts

@@ -329,9 +329,9 @@ export function getClaudeTempDirName(): string {
 // and per-turn from BashTool prompt. Inputs (CLAUDE_CODE_TMPDIR env + platform) are
 // fixed at startup, and the realpath of the system tmp dir does not change mid-session.
 export const getClaudeTempDir = memoize(function getClaudeTempDir(): string {
-  const baseTmpDir =
-    process.env.CLAUDE_CODE_TMPDIR ||
-    (getPlatform() === 'windows' ? tmpdir() : '/tmp')
+  // tmpdir() honors $TMPDIR so non-/tmp environments (Termux/Android, containers)
+  // work out of the box; CLAUDE_CODE_TMPDIR still wins if explicitly set.
+  const baseTmpDir = process.env.CLAUDE_CODE_TMPDIR || tmpdir()
 
   // Resolve symlinks in the base temp directory (e.g., /tmp -> /private/tmp on macOS)
   // This ensures the path matches resolved paths in permission checks