bundle add: accept fully-qualified names from untapped taps

[p-linnane]

brew bundle add rejected fully-qualified formula and cask names from untapped taps, failing before it wrote anything to the Brewfile (reported in #23265). brew install and brew bundle install both treat a fully-qualified name as explicit consent to install its tap, but brew bundle add kept neither carve-out after the "Stop implicit tap installation" change, so the same name accepted by brew install was refused by the command whose whole job is writing that entry.

This mirrors brew install: for a fully-qualified formula or cask argument it installs the tap and applies formula- or cask-specific trust before loading the item for its description and validation. Unqualified names still never cause an implicit tap install, and tap and extension entries keep their existing behavior.

Fixes #23265

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

Claude Code (Opus 4.8) drafted the implementation and tests; I reviewed the diff, verified the new tests fail without the fix and pass with it, and ran brew lgtm + targeted specs.

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[Copilot]

Pull request overview

This pull request updates brew bundle add to accept fully-qualified formula and cask names from taps that are not currently installed, aligning its behaviour with brew install and avoiding early failures when the user is explicitly naming a tap-owned item.

Changes:

• Ensure the tap for a fully-qualified formula/cask argument is installed before attempting to load it.
• Apply item-level trust for fully-qualified formulae/casks (where applicable) before loading, to satisfy the trust model.
• Add specs covering the fully-qualified formula and cask cases from an untapped tap, including operation ordering.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/bundle/adder.rb	Installs the tap (for fully-qualified items) and applies item trust before loading formulae/casks for validation/description.
Library/Homebrew/test/cmd/bundle/add_subcommand_spec.rb	Adds tests ensuring tap install and trust occur before loading fully-qualified formulae/casks from untapped taps.

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[MikeMcQuaid]

Makes sense, thanks!