Salvages #26745 by @nehaaprasaad. Exposes filtering for the existing
workflow_template_id and current_step_key columns:
- list_tasks() accepts workflow_template_id and current_step_key kwargs
- 'hermes kanban list' adds matching CLI flags
- dashboard plugin_api also exposes the filters
Resolved a small conflict in list_tasks signature alongside main's
session_id and order_by additions; combined all three into the single
filter list.