OptionalnowClock override for tests.
OptionalpendingAge (ms) after which a 'pending' reservation counts as abandoned — a
crashed isolate — and may be taken over. Must exceed the longest
expected execute duration, or a slow-but-alive execution races its own
takeover. A takeover while the original holder is still running can
execute a write connector twice. Default 900 000 — above
agent-cli's default 600 000ms execute timeout; agent-cli's
idempotencyKey option additionally throws at definition time when a
configured store's pendingTtlMs does not clear its timeoutMs.
OptionaltableTable name (default 'breakwater_idempotency').
Configuration for D1IdempotencyStore.