SwifterPM cached-directory-materialization is configurable via install passthrough

Tuist now exposes the SwifterPM cached-directory-materialization option through the existing install passthrough path. You can set it via Config.project.generatedProject.installOptions.passthroughSwiftPackageManagerArguments or the TUIST_INSTALL_PASSTHROUGH_ARGUMENTS environment variable, for example –cached-directory-materialization,symlink. This keeps the CLI surface smaller and avoids adding a dedicated environment variable for one SwifterPM option.