Write Section Promise

Four tests

A promise passes if ALL of:

1. Specific — reader can predict what a post in this section will do for them.
2. Testable — point at a candidate post and say yes/no.
3. Non-overlapping — distinguishable from every other section's promise by at least one axis.
4. Voiced — reads as the writer's voice per audience-notes.md + voice-profile.md, not marketing copy.

Workflow