Add ask dependency plans and cask support

[MikeMcQuaid]

• Show added, changed and removed packages before --ask mutates installs, upgrades or reinstalls.
• Include cask dependency support so --ask/HOMEBREW_ASK covers both cask and formula changes.

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[Copilot]

Pull request overview

This PR expands --ask behavior to show dependency plans for formula and cask install/upgrade/reinstall flows, and updates user-facing documentation/completions accordingly.

Changes:

• Adds dependency-plan output for formulae and casks, including added/changed/removed closure entries.
• Wires cask --ask handling into install, upgrade, and reinstall paths.
• Updates manpage, docs, env config, and shell completion descriptions for --ask.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Library/Homebrew/install.rb	Implements formula/cask ask-plan output and configurable prompt action text.
Library/Homebrew/cmd/install.rb	Moves cask ask handling to planned fetch casks and adds ask-mode hints.
Library/Homebrew/cmd/upgrade.rb	Adds cask ask handling for discovered outdated casks and updates option text.
Library/Homebrew/cmd/reinstall.rb	Adds cask ask action wording for reinstall and updates option text.
Library/Homebrew/env_config.rb	Updates HOMEBREW_ASK description.
Library/Homebrew/test/cmd/install_spec.rb	Adds tests for formula/cask ask-plan output and hints.
Library/Homebrew/test/cmd/upgrade_spec.rb	Adds cask upgrade ask test.
docs/Manpage.md	Updates generated/user documentation text.
manpages/brew.1	Updates generated manpage text.
completions/fish/brew.fish	Updates fish completion descriptions.
completions/zsh/_brew	Updates zsh completion descriptions.

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[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.