Adds a new test-install-tools job to the test workflow that exercises the spec input path of the action end-to-end.

What's tested:

• A minimal Lucafile fixture is written at runtime, declaring two publicly available tools:
  • Tuist 4.80.0
  • SwiftLint 0.61.0
• The action is run with spec: Lucafile, installing both tools and adding them to PATH.
• Each tool is verified to be reachable on PATH and to report the exact expected version.
• Each tool's symlink under ~/.luca/tools/ is verified to point to the correct versioned path:
  • ~/.luca/tools/tuist → ~/.luca/tools/Tuist/4.80.0/tuist
  • ~/.luca/tools/swiftlint → ~/.luca/tools/SwiftLint/0.61.0/SwiftLintBinary.artifactbundle/swiftlint-0.61.0-macos/bin/swiftlint

This gives confidence that the tool caching and symlinking logic resolves binaries correctly from the versioned store.