0.8.7 shipped a stale dist: dist/ is gitignored and there was no
prepublish build step, so npm published whatever build happened to be in
the working directory (a Feb 11 build). The published 0.8.7 tarball is
byte-identical to 0.8.6 apart from the version string, so the cache
transaction sweeper from 393c571 never reached consumers.

Add prepublishOnly so the package is always rebuilt from source before
publishing, and bump to 0.8.8 (npm forbids republishing 0.8.7).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

fake-indexeddb's Database.transactions array is append-only: finished
transactions are never removed, so long-lived Node processes retain
~5-7KB per cache operation until restart and rescan the growing array on
every operation. This is the root cause of the daily memory sawtooth on
allo staging (diagnosed 2026-09-02; unfixed upstream as of 6.2.5).

Add a 10s sweeper interval, active only when the IndexedDB shim is in
use, that drops finished transactions from the array. Safe because every
upstream reader filters on transaction state. Verified: 500 saves leave
502 retained transactions before, 0 after the sweep, with all rows still
queryable.

Interim mitigation until the cache gets a proper Node backend (bounded
Map/LRU instead of the IndexedDB shim).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>