Revert #2574 (notify-based runner-lock wake) once rocksdb-js with #849 is pinned #2576

#2574 is a temporary workaround, not the design. It takes the derived-index runner lock without an unlock callback and wakes waiting runners through the readiness buffer's notify(), a self-notification skip, and a 5 s retry timer — because with the pinned rocksdb-js, a tryLock(key, callback) waiter queued by a worker that is later terminate()d aborts the process on Node 22 when another thread unlocks (rocksdb-js#848). That is a bug in the primitive, fixed at the root by rocksdb-js#849 (a dying env's queued lock callbacks are released from its cleanup hook; the release paths hold locksMutex across the tsfn calls).

The lock's own unlock callback is the simpler and more correct wake: one primitive, and a holder that dies releases natively and wakes the waiters immediately, where the workaround waits for a commit or up to 5 s. Once the fix is pinned, revert.

Checklist

• rocksdb-js release containing Fix circular dependency causing jsLoader tests to fail in isolation #849 is published
• @harperfast/rocksdb-js pin bumped in harper main (and any release line that took Temporarily take the derived-index runner lock without an unlock callback (rocksdb-js#848 workaround) #2574)
• revert Temporarily take the derived-index runner lock without an unlock callback (rocksdb-js#848 workaround) #2574 (git revert, resolving resources/derivedIndexRuntime.ts back to tryLock(this.#lockKey, retry) and dropping #skipNextNotify / #lockBackoff / LOCK_RETRY_MILLISECONDS; restore the removed "synchronous unlock callback" test in derivedIndexRuntime.test.js)
• unitTests/resources/vectorIndexPlane.test.js passes on Node 22 with the new pin and the callback path (this is the suite that aborted main's Node 22 CI)
• DESIGN.md § Derived-index runtime › Ownership and wake-up: replace the "Temporarily … tracked revert" paragraph with the callback description and a one-line note that the notify path existed until rocksdb-js ⟨version⟩

Verification that the fix alone suffices: main's runtime unchanged against a #849 binary passes vectorIndexPlane.test.js 22/22 on Node 22.23.1.

Refs #2574, #2430, #2489.