[BUG] npm install broken on non-AVX Linux x64 CPUs since v2.1.113 — Node.js (cli.js) fallback removed

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Since v2.1.113, npm install -g @anthropic-ai/claude-code installs a Bun standalone binary (bin/claude.exe) that crashes immediately on Linux x64 CPUs without AVX support. Prior to v2.1.113, the package shipped cli.js with a #!/usr/bin/env node shebang which ran on the system's existing Node.js — no Bun required. That file has been removed.

What Should Happen?

Claude should launch successfully on non-AVX Linux x64 CPUs when installed via npm. Either the Node.js-compatible cli.js entrypoint should be restored as a fallback, or a Bun baseline build that genuinely supports non-AVX CPUs should be shipped.

Error Messages/Logs

Bun v1.3.13 (6db6c97b) Linux x64 (baseline)
  Linux Kernel v6.12.57 | glibc v2.41
  Features: jsc no_avx2 no_avx standalone_executable claude_code
  CPU lacks AVX support. Please consider upgrading to a newer CPU.
  panic(main thread): Segmentation fault at address 0x243B0C00000
  oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Steps to Reproduce

1. Have a Linux x64 machine/VM without AVX CPU support
2. Install Node.js 20.x
3. Run npm install -g @anthropic-ai/claude-code (installs v2.1.113+)
4. Run claude
5. Bun segfaults immediately

Pinning to npm install -g @anthropic-ai/claude-code@2.1.112 (last version with cli.js) works correctly.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.112

Claude Code Version

2.1.117 (latest at time of filing)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Non-interactive/CI environment

Additional Information

The linux-x64 optional package (@anthropic-ai/claude-code-linux-x64) was first introduced in v2.1.110 but cli.js was retained until v2.1.112. v2.1.113 is the exact version where cli.js was dropped and the bin entry switched to bin/claude.exe.

The Bun binary correctly identifies itself as a baseline build (no_avx2 no_avx) but still segfaults — this appears to be a regression in Bun 1.3.x where even the baseline standalone executable crashes on truly AVX-less CPUs.

Related issues: #50270 (same root cause, affects Termux/Android), #33153 (no-AVX Bun crash, open since 2.1.85+)