fix: bunker replay protection + sync quota fallback (deferred audit items)

[vveerrgg]

Follow-up to #1 — the two contained, well-tested deferred items from the audit pass. Stacked on fix/nsec-import-and-backup; will retarget to main once #1 merges.

Bunker replay protection (bunker-server.js)

The NIP-46 server signs requests from authenticated clients. Without replay protection, a captured authenticated sign_event event could be re-published to the relay and re-signed.

• _isFreshEvent() rejects request ids already processed (bounded seen-set, 500) and events whose created_at is outside a ±5min window.
• State cleared on stop().

Sync quota fallback (sync-manager.js)

storage.sync.set is all-or-nothing: an over-quota batch was rejected whole and silently synced nothing — not even P1 profiles.

• setSyncRespectingQuota() drops the lowest-priority entries and retries, guaranteeing P1 (profiles) syncs. Logs what it dropped (no silent truncation). Throws only if P1 + meta alone exceeds quota.

Tests

• test/bunker-replay.test.js (7), test/sync-quota.test.js (4). Full suite: 181 passed, 2 skipped.

Deliberately NOT included — needs a design decision

Sync deletion tombstones. While scoping it I found vault docs live on Nostr relays (NIP-78) and vault.delete publishes a NIP-09 deletion to relays — storage.sync is only a mirror of a local cache. So deletion propagation is entangled with the relay layer, not a pure sync-schema addition. It needs a dedicated design pass to reconcile the relay deletion path with the sync mirror, rather than a half-correct tombstone bolted onto storage.

🤖 Generated with Claude Code

[vveerrgg]

Superseded by the v1.7.0 security hardening merged to main (fix/security-audit-2026-07) — bunker per-connection/default-deny signing, encrypt-at-rest + never-sync-plaintext, NIP-06 fix, key-theft trust boundary. v1.7.0 shipped (App Store accepted 2026-07-20). This branch is an earlier parallel implementation of the same fixes and conflicts with the shipped version, so closing rather than re-applying older/duplicate hardening. Branch retained if any stray change needs cherry-picking.