Add install step rebuild actions

[MikeMcQuaid]

• avoid Ruby-only post_install for common desktop cache rebuilds
• keep API steps structured instead of serialising raw commands
• document supported actions and examples for formulae and casks

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• AI was used to generate or assist with generating this PR.

OpenAI Codex 5.5 xhigh with local review.

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[github-code-quality]

Code Coverage Overview

Languages: Ruby

Ruby / code-coverage/simplecov

The overall coverage in the install-step-rebuild... branch is 75%. The coverage in the main branch is 78%.

Show a code coverage summary of the most impacted files.

File	main 53d2800	install-step-rebuild... 4079bd0	+/-
cask/info.rb	96%	0%	-96%
cask/installer.rb	91%	28%	-63%
cask/artifact/a...ct_uninstall.rb	89%	32%	-57%
cask/audit.rb	63%	25%	-38%
cask/cask_loader.rb	96%	65%	-31%
bundle/extensions/flatpak.rb	37%	94%	+57%
extend/os/linux/diagnostic.rb	0%	67%	+67%
os/linux/elf.rb	0%	86%	+86%
extend/os/linux/sandbox.rb	0%	95%	+95%
extend/os/linux...ystem_config.rb	0%	99%	+99%

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_{Updated June 02, 2026 16:49 UTC
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[p-linnane]

Much cleaner!