Add work order failure-code categorization scenarios

[ShuxinLin]

Summary

There are currently no workorder-type evaluation scenarios under src/scenarios/local/ — only vibration_utterance.json. Add a focused set of scenarios that exercise the wo/ server's failure-code categorization capabilities (get_failure_codes, get_work_order_distribution).

Scope

A new src/scenarios/local/workorder_utterance.json with ~5-6 scenarios covering:

• Knowledge query: list failure-code categories / codes under a category
• Categorization: map a failure code (or WO description) to its category
• Distribution analysis: group an asset's work orders by failure-code category

Each scenario follows the existing schema (id, type, text, category, characteristic_form) and is validated by an evaluation loader test.

Acceptance criteria

• New scenario JSON file parses via load_scenarios
• A test validates the file loads and conforms to the Scenario schema
• Unit tests pass (uv run pytest src/ -v -k "not integration")

[DhavalRepo18]

@ShuxinLin, please coordinate on our revised code first. We will give you a proper design; we may not release all the hard scenarios publicly.