[JieXiong9119]

Why do we need this PR

This is PR 10 of the scenario workflow plan. Baseline OSW assembly was mixed into the file-writing code in write_baseline_osw. Moving it into a separate builder lets later scenario PRs reuse the baseline workflow without writing it to disk first.

Core change explanation

• Added a private BOSS.build_baseline_osw(bsync_reader) that loads the template, runs the eight baseline populators, calls configure_osw, orders measure and file paths (local → gem → external), and returns the OSW hash.
• write_baseline_osw now validates the XML, builds the reader, calls the builder, and writes baseline/in.osw. Its public API, CLI behavior and output layout are unchanged.
• run_baseline_osw is unchanged.

Which files are affected

• lib/BOSS/boss.rb
• spec/tests/unit/boss_spec.rb
• docs/scenario_workflow_translation_plan.md

What kind of tests are done

• New unit tests check that:
  • the workflow steps generated for building_151 and all_measures_applied_example are identical to the pre-refactor output,
  • a missing XML file raises an error,
  • output paths with spaces work,
  • writing the OSW does not start a run,
  • the builder is private and returns a fresh hash on each call,
  • measure and file paths keep their exact order.
• bundle exec rspec spec/tests/unit: 112 examples, 0 failures.
• bundle exec rubocop lib/BOSS/boss.rb spec/tests/unit/boss_spec.rb: the only new offense is Metrics/BlockLength on the spec's top-level block.
• Baseline simulation for building_151 and all_measures_applied_example: both succeeded, all 8 steps completed. I checked the generated models against the source XML; they match apart from defaults used where the XML has no data.
• Not yet run: the full integration spec (bundle exec rspec spec/tests/integration/write_and_run_osws_spec.rb) and bundle exec rake.

Out of scope / Follow-up work

• The integration spec always stubs San Francisco weather, so all_measures_applied_example (Denver, climate zone 5B) runs with the wrong weather file. Fix by stubbing weather per fixture.
• BOSS doesn't map the XML's operating hours to the model's building hours (both runs warn about this). Handle this in input-mapping work.
• Running the external measures requires rake measures:install_external; without it, the run fails with "Cannot find measure 'replace_baseline_windows'".