[Agent Substrate] Enforce Upfront Discussion Criteria Mapping in ideation-sandbox and ticket-create (#11328 follow-up: optional ergonomics)

What is the purpose of this issue?

Add lightweight upfront mapping format requirements to ideation-sandbox and ticket-create for Discussion-origin Epics.

What is the context?

This is part 3 of 3 to close the "Discussion-graduation enforcement gap" identified in the #11328 audit. To make the new gates in epic-review and epic-resolution cheap to evaluate, the upstream creation workflows should standardize the inclusion of a mapping table right from the start.

Scope Singularity Exception Rationale: This ticket intentionally bundles two skill modifications (ideation-sandbox and ticket-create) because both pointers are 1-line additions and must land together to avoid asymmetric upstream contracts.

Acceptance Criteria

• Update ideation-sandbox §6.7 (Author Actions) to require the created Epic/artifact to include a ## Discussion Criteria Mapping section when graduating a Discussion that has graduation criteria.
• Update ticket-create (specifically the high-blast Discussion-origin flow) to include a pointer/instruction to include this same mapping section.
• Ensure these changes are small routing contracts and do not bloat the skills excessively.

Priority

• priority:high
• ai