feat: add Slack CLI command runner workflow and installer composite action

[ewanek1]

Summary

This PR builds upon #486. It continues iterating on the GitHub composite action and workflow that runs Slack CLI commands directly in CI/CD.

Notes on Changes

Added action inputs for common flags including verbose and CLI version

Re-running a workflow automatically enables verbose output

Removed the flag-parsing script in favor of direct command execution via slack ${{ inputs.command }}

Added --skip-update flag to prevent auto-updates during installation

Enabled SLACK_DISABLE_TELEMETRY variable so usage won’t bump up numbers in collecting metrics

Updated logging to match GitHub's logger

Moved major logic into action.yml as a proper composite action

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.86%. Comparing base (a560f02) to head (c7d8f2c).

Additional details and impacted files

@@ Coverage Diff @@## feature/slack-cli-runner #488 +/- ##
=========================================================
Coverage 99.86% 99.86% =========================================================
Files 7 7 Lines 722 722 =========================================================
Hits 721 721 Misses 1 1 

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[zimeg]

@ewanek1 This is an awesome set of changes! Things are looking good to me and I plan to share more thoughts soon but I'm excited for the feature branch and iteration to follow 👾 ✨

[zimeg]

📝 note: Changes of dev exist in this PR: slackapi/slack-cli#178

👁️‍🗨️ suggestion: I might've shared an incomplete command with this link too but perhaps this brings better luck? Let's keep note to test this at some point-

Suggested change

	irm https://downloads.slack-edge.com/slack-cli/install-windows-dev.ps1
	irm https://downloads.slack-edge.com/slack-cli/install-windows-dev.ps1 | iex

[ewanek1]

Luckily I think this let the CLI install properly! Although now it hangs on the very last step in the script. It echoes the command Run slack version --skip-update but doesn't go any further 🤔 Before this I got this error The term 'slack' is not recognized as a name of a cmdlet so I wonder if it has to do with the PATH variable. I'll keep trying to look into this!

[zimeg]

👋 Closing in favor of #489 with super good direction in these changes! 👾