Adding a second hashtag interest/disinterest quickly showed "didn't work" yet the
change persisted after a refresh. Cause: the replaceable preferences event used
created_at = floor(now/1000), so two edits in the same wall-clock second produced
the SAME created_at. Relays reject the second as "not newer" (client shows an
error) while relays that break created_at ties by id still store it (so it appears
after a refresh) — an inconsistent false-negative.
Fix: nextReplaceableCreatedAt(lastCreatedAt) (js/nostr/replaceableCreatedAt.js) —
always advance to max(now, lastCreatedAt + 1), so each publish is strictly newer
than the last and every relay accepts it unambiguously. Reusable for the other
replaceable lists (subscriptions/blocks) that have the same latent collision.
Tests: tests/replaceable-created-at.test.mjs (5 — same-second bump, clock-ahead,
no-prior, rapid successive strictly-increasing, floors fractional). Lint + build green.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
