Combine dependency role tags from API metadata #24302

Formulae loaded from the API split a dependency with more than one role, such as depends_on "foo" => [:build, :test], into separate :build and :test dependencies, while loading the formula's Ruby source keeps one Dependency with both tags. FormulaStructGenerator.process_dependencies now unions each name's role tags in a fixed order (:build, :test, :recommended, :optional, then :no_linkage) so API-loaded formulae get the same dependencies as source-loaded ones; separate :build and :test declarations of one name also load as one combined dependency. Runtime entries stay separate, so a formula that depends on gettext and also declares it :build keeps it in both dependencies and build_dependencies from Formula#to_hash. The round-trip examples now cover a runtime dependency with combined tags, compare the Formula#to_hash dependency lists and stub the API metadata Formula#to_hash reads so they run offline. Brew versions before 7.0.10 (#24262) reject array-valued tags in the internal API when HOMEBREW_SORBET_RUNTIME is set.

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Codex (GPT-6 Astra) wrote the change and tests, compared source and API-loaded dependencies across homebrew/core for all 16 OS/arch tags, checked the new examples fail before the change on host and --generic and ran brew lgtm --online. Claude Code (Opus 5.5) reviewed it, found that an earlier version dropped runtime dependencies from the Formula#to_hash role lists, reran the comparison on the final version for the formulae whose output could change, checked the new examples fail on the previous code offline on host and --generic, rebased onto current main and ran brew lgtm --online on this commit.

Summary by CodeRabbit

• 
  Bug Fixes
  
  
  • Improved dependency metadata handling to remove duplicate entries and preserve all applicable dependency types.
  
  
  • Dependencies can now retain multiple tags, including build, test, recommended, optional, runtime and no-linkage classifications.
  
  
  • Dependency metadata round-trips now more reliably preserve these classifications and their ordering.