SIGSEGV on startup in v2.1.242+ on Linux (glibc 2.44, x86-64)

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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?

Running `claude` (including `claude --version`) immediately crashes with a segmentation fault (SIGSEGV) starting in v2.1.242. The crash happens right after loading the standard shared libraries (librt, libc, libpthread, libdl, libm) — before any application files are opened. Signal is `SEGV_MAPERR` at `si_addr=NULL` (null pointer dereference in the SEA binary).

### What Should Happen?

Claude Code should start successfully and print the version, as it did in v2.1.241 and earlier.

### Error Messages/Logs

```shell
$ claude --version
zsh: segmentation fault (core dumped) claude --version
$ echo $?
139

strace output (last lines before crash):
openat(AT_FDCWD, "/usr/lib/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
mmap(NULL, 1270088, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9e2e4a0000
mmap(0x7f9e2e4b0000, 638976, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x10000) = 0x7f9e2e4b0000
mmap(0x7f9e2e54c000, 561152, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xac000) = 0x7f9e2e54c000
mmap(0x7f9e2e5d5000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x134000) = 0x7f9e2e5d5000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9e2e49e000
mmap(NULL, 36864, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9e2e495000
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---
+++ killed by SIGSEGV (core dumped) +++
```

### Steps to Reproduce

1. Install v2.1.242 or v2.1.243: `npm install -g @anthropic-ai/claude-code@2.1.242`
2. Run `claude --version`
3. Observe segmentation fault

Bisection results:
- v2.1.241: works correctly
- v2.1.242: SIGSEGV on startup
- v2.1.243: SIGSEGV on startup

### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

2.1.241

### Claude Code Version

2.1.243 (Claude Code)

### Platform

Anthropic API

### Operating System

Other Linux

### Terminal/Shell

Other

### Additional Information

Shell: zsh
Kernel: 6.12.104-1-MANJARO
glibc: 2.44
Node.js (via nvm): v24.19.0
Binary: ELF 64-bit LSB, dynamically linked (Node.js SEA), ~361 MB

Workaround: pin to v2.1.241 (`npm install -g @anthropic-ai/claude-code@2.1.241`)

Reproduce the crash with `claude --version` using @anthropic-ai/claude-code v2.1.242 or v2.1.243 on Linux with glibc 2.44, and compare it with v2.1.241. Start with the reported strace boundary and the Node.js SEA binary; use the core dump if available. Done means the CLI starts and prints its version without SIGSEGV on the affected environment.

Written by the indexing model from the issue text.