Use cask tab to better identify installed casks

Previously we would identify installed casks by token derived from
directories present in the caskroom directory. That was error prone
when the token was ambiguous. In that case, the `Cask::Caskroom.cask`
method would default to the first cask which was not always correct.

Now that we have the cask tab we can use the installed receipt to
get the tap a cask came from. With both the tap and the token, we
can be sure that we're loading the cask that is actually installed
and not another cask from a different tap that just happens to have
the same name.

Library/Homebrew/cask/caskroom.rb

@@ -28,6 +28,23 @@ def self.tokens
  paths.map { |path| path.basename.to_s }
  end
 
+ sig { returns(T::Array[String]) }
+ def self.full_tokens
+ require "cask/tab"
+
+ paths.map do |path|
+ token = path.basename.to_s
+ # Cask tabs were only added on July 13, 2024 in
+ # https://github.com/Homebrew/brew/pull/17554 so
+ # they might not exist for older installs.
+ if (tab_path = path/".metadata"/AbstractTab::FILENAME).exist?
+ tap = Tab.from_file(tab_path).tap
+ token = "#{tap}/#{token}" if tap
+ end
+ token
+ end
+ end
+
  sig { returns(T::Boolean) }
  def self.any_casks_installed?
  paths.any?
@@ -55,7 +72,7 @@ def self.ensure_caskroom_exists
  # @api internal
  sig { params(config: T.nilable(Config)).returns(T::Array[Cask]) }
  def self.casks(config: nil)
- tokens.sort.filter_map do |token|
+ full_tokens.sort.filter_map do |token|
  CaskLoader.load(token, config:, warn: false)
  rescue TapCaskAmbiguityError => e
  T.must(e.loaders.first).load(config:)