Summary

Companion to #555 / #556. Even after we lower the build target with cargo-zigbuild, the npm wrapper currently exits successfully on install and only fails later at first launch with a runtime linker error like `libc.so.6: version 'GLIBC_2.39' not found`. The user has no clue what just happened.

Proposal

In the npm postinstall script (`npm/deepseek-tui/scripts/postinstall.js` or equivalent), after downloading the binary:

1. Detect the host glibc version (Linux only): `ldd --version` parse, or `getconf GNU_LIBC_VERSION`.

2. Detect the binary's required glibc: `readelf -V | grep GLIBC_` and pick the highest version.

3. If host < required, print a clear error and direct the user to the source-build path:

   `deepseek-tui requires glibc >= 2.28 (your system has 2.17). Install from source instead: `cargo install deepseek-tui-cli``

4. Exit non-zero so npm flags the install as failed, instead of the current "looks fine, fails later" UX.

Repro context

Reported by @20bytes on issue #555 (Ubuntu 22.04, glibc 2.35) — install succeeds, both `./node_modules/.bin/deepseek --version` and `./node_modules/.bin/deepseek-tui --version` fail at runtime with the linker error.

Notes

• macOS / Windows path: skip the check, no glibc concept.
• After fix(ci): use cargo-zigbuild to lower Linux glibc requirement to 2.28 #556 lands and the floor drops to glibc 2.28, this preflight stays useful for the long tail of CentOS 7 / RHEL 7 (glibc 2.17) users.