0.31.0

Changed

• An edge no longer moves its source document's revision. protocol artifact relate (and new --relate) wrote the edge into the source's frontmatter and counted that as a revision, so the same plan answered revision 2 on markdown and revision 1 on SQLite. The contract never counted a relation as a revision of either endpoint, and now no store does: the document changes, the event lands at the revision the document already had, and store_selection.rs compares revision numbers exactly again. The golden fixture was re-recorded with this build; expected/ and reads/ are no longer 0.28.0's bytes for that one verb, and golden_plan.rs says so (story:relation-bumps-a-document-revision-but-not-an-entity).

Fixed

• protocol artifact evidence accepts the instant it defaults to. Without --at the verb produced YYYY-MM-DDTHH:MM:SSZ and its own reader knew only a date or epoch milliseconds, so every recording had to type --at. The reader now takes the second-resolution form too (story:evidence-verb-refuses-its-own-default-instant). Fixing it exposed two more things the same defect had hidden: store_selection.rs had compared two identical failures and called the stores alike — it now asserts every write's exit code — and a SQLite or Postgres plan counted no evidence on hand at all, because an accepted command's audit record names its subject and not the kind of evidence it recorded (the contract keeps decision for refusals). Evidence on hand is now counted from the entity's events, the same source history reads, so an evidence-gated move over SQLite is decided on what was recorded.

• epic:planning-store-as-backend is implemented: fifteen stories implemented, one archived as superseded (story:sqlite-backend), one follow-on filed and delivered above.