Fixes #6931

Summary

This PR replaces the use of the prepare script with a safer postinstall-based Husky setup that only runs in contributor environments. This ensures that consumers of Axios can install it from GitHub or tarballs without encountering errors related to Husky, even in environments without a .git directory.

Previously, Axios's prepare script included Husky install logic that assumed the presence of a .git directory. This caused installation failures in environments such as:

• CI pipelines
• Monorepos
• Git-based installs from forks or branches (e.g., npm install github:axios/axios)

To prevent this while preserving automatic Git hook setup for contributors, this change moves the Husky logic into a guarded shell script executed during postinstall, but only when a .git directory is present.

Changes

• Removed the "prepare" and "prepare:hooks" scripts from package.json
• Added "postinstall" with a guarded scripts/setup-husky.sh script that:
  • Runs husky install (same as before)
  • Sets up the commit-msg hook using commitlint (same as before)
  • Skips setup entirely if .git/ is not present (new)
• Updated .npmignore to ensure the script is included in the published tarball. Otherwise, npm install will fail.
• Replaced usage of npx with direct binary references for environments where npx may not be available