Add cross-platform CLI Installers

[hanouticelina]

Resolves #3373
This PR adds cross-platform installers for the CLI so MacOS/Linux/Windows users can install hf CLI with a single command. a new workflow is also introduced running both installers on Ubuntu and Windows to make sure it works correctly.
Key features (subject to change):

• --force: optional reinstall flag to wipe and rebuild the virtualenv for a clean recovery.
• --version: install a specific huggingface_hub release instead of latest (default).
• -v/--verbose: verbose mode surfacing full pip output for debugging.
• env variable support letting users tune pip behavior without rewriting the script.
• post-install verification that runs hf immediately to confirm it’s callable.
• Uninstall instructions printed at the end for easy cleanup. (maybe not useful?)

TODO

• Update all docs to highlight the new cross platform installer commands.

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Notes

• Both files are expected to be served from https://hf.co/install.sh and https://hf.co/install.ps1.
• both scripts are based on an initial version here (private) and fixed with the help of GPT-5 (especially for the windows one!).
• No strong opinion on where to put them in the repo 😄

Usage

(with temporary GH links)

### macOS / Linux
curl -LsSf https://raw.githubusercontent.com/huggingface/huggingface_hub/e5b3d11d4e868172e7f299b7d4cfcfe531219bc4/utils/installers/install.sh | sh

# Force reinstall:
curl -LsSf https://raw.githubusercontent.com/huggingface/huggingface_hub/e5b3d11d4e868172e7f299b7d4cfcfe531219bc4/utils/installers/install.sh | sh -s -- --force

### Windows (PowerShell 5+ or pwsh)
powershell -NoProfile -ExecutionPolicy Bypass -Command "irm https://raw.githubusercontent.com/huggingface/huggingface_hub/
  e5b3d11d4e868172e7f299b7d4cfcfe531219bc4/utils/installers/install.ps1 | iex"

# Force reinstall:
powershell -NoProfile -ExecutionPolicy Bypass -Command "irm https://raw.githubusercontent.com/huggingface/huggingface_hub/
  e5b3d11d4e868172e7f299b7d4cfcfe531219bc4/utils/installers/install.ps1 | iex -force"

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[Wauplin]

Left a few minor comments but unix installer looks good to me 👍

About powershell, let's ask copilot opinion 😄 (it seems to work in the CI but definitely not familiar here)

[Copilot]

Pull Request Overview

This PR adds cross-platform CLI installers for the Hugging Face CLI, allowing users on macOS, Linux, and Windows to install the hf CLI with a single command. The installers create isolated virtual environments and provide comprehensive configuration options.

• Bash script for macOS/Linux with automatic shell detection and PATH management
• PowerShell script for Windows with user PATH integration
• GitHub Actions workflow to validate both installers on Ubuntu and Windows

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 14 comments.

File	Description
utils/installers/install.sh	Cross-platform bash installer with virtual environment management, PATH updates, and comprehensive logging
utils/installers/install.ps1	Windows PowerShell installer with similar functionality adapted for Windows environment
.github/workflows/check-installers.yml	CI workflow to test both installers automatically on push and PR

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