Add Workflow Preset to community catalog (#2725)

* Add Workflow Preset to community catalog

Add workflow-preset submitted by @bigsmartben to:
- presets/catalog.community.json (alphabetical order)
- docs/community/presets.md community presets table

Closes #2618

* Fix Requires column: use — for no required extensions

The Requires column lists required extensions, not the Spec Kit
version. This preset has no extension dependencies.