[agent-harness] P4.1 ADR - idempotent vs non-idempotent agent flows

[ManintheCrowds]

Phase 1 — P4.1

Outcome: Short ADR: which operations are safe to retry; links from SYNC_SESSION_HANDOFF.md and CLARIFICATION_QUEUE_API.md.

Seed: P4 backlog

Acceptance criteria

• Lists clarification, alignment, survey (and related) with retry semantics.
• Linked from the two docs above (or single index that both reference).

Blocks: P4.2

[ManintheCrowds]

Repo naming: Canonical policy and checklist — docs/engineering/OPENGRIMOIRE_NAMING_AND_URLS.md (GitHub ManintheCrowds/OpenGrimoire, local folder OpenGrimoire).