Release v0.3.1

[0.3.1] - 2026-06-05

Fixed

• nitrite-fjall-adapter — transactional reads inside an active Fjall atomic scope no
  longer rely on Fjall 2.11.2's KV-separated WriteTransaction read helpers. The adapter now
  reconstructs read-your-writes semantics from committed partition reads plus a scoped
  transaction overlay, so commits that touch unique indexes succeed on kv_separated(true)
  stores instead of failing with MaybeInlineValue decode errors.
• nitrite-int-test — added a KV-separated unique-index transaction regression that
  exercises both Durability::Periodic and Durability::OnCommit, validates immediate
  post-commit reads, and verifies the data/index pair still agrees after reopen.