feat!: improve curl safety, non-apt warnings, and add outputs

[abn]

Description

This PR improves the code quality, security, and developer experience of the setup-cli composite action. It also introduces structured outputs and better warnings for non-Debian based Linux environments.

This change includes a breaking change footer to instruct release-please to trigger the first major release (v1.0.0).

Key Enhancements

1. Security & Code Quality (Resolved eval smells):

   • Replaced string-interpolated eval commands for injecting GITHUB_TOKEN authentication with bash arrays (AUTH=()). This prevents authentication tokens from appearing in execution traces and makes command structure robust.

2. Robust Fallbacks:

   • Added || true to the public API curl command in the version resolution block to ensure transient network issues do not abruptly trip pipefail / errexit before the action can output a friendly error message.

3. Exposed Action Outputs:

   • Added outputs to the action:
     • version: The resolved version tag of the AetherPak CLI that was installed.
     • path: The absolute installation directory.
   • Useful for downstream workflow tasks and testing automation.

4. Non-Apt OS Warnings:

   • Emits a GitHub Action ::warning:: if the runner is missing required packages but has no apt-get package manager installed (e.g., self-hosted Fedora or Arch Linux runners), rather than failing silently.

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BREAKING CHANGE

This action now enforces strict Linux OS verification, refactors token interpolation to use array expansion, and introduces new action outputs.