fix(kv-store): skip pool creation on ephemeral deleteDb to unstick browser tests

[AztecBot]

What

Forward-port of PR #22693 from merge-train/spartan to merge-train/fairies. The kv-store SQLite-wasm-over-OPFS change (#22658) is now in fairies via the latest next → fairies merge, but the fix from #22693 has not yet propagated, so every fairies merge-train CI run is timing out on the kv-store browser tests.

yarn-project/kv-store/src/sqlite-opfs/worker.ts::handleDeleteDb installs an OPFS SAH Pool on every teardown, even for :memory: ephemeral DBs (which never back a file). The OPFS SAH Pool acquires an exclusive directory lock; under heavy test churn + --cpus=2 CI contention, the next test's pool install can block indefinitely waiting for the previous terminated worker's OPFS handles to release. The deleteDb RPC has no timeout, so afterEach hangs and the whole yarn test run times out.

All kv-store browser tests use AztecSQLiteOPFSStore.open(mockLogger, undefined, true) (ephemeral), so handleInit never sets up a pool — handleDeleteDb has nothing to unlink. Skip the pool install in that case. Non-ephemeral stores are unchanged.

Failing CI

• Run: https://github.com/AztecProtocol/aztec-packages/actions/runs/24735702716
• Log: http://ci.aztec-labs.com/1776789206174897 → kv-store step http://ci.aztec-labs.com/8803271311dc9faf
• Symptom: yarn test killed by timeout 600s (exit 124); 10 minutes of silence after the last sqlite-opfs test line.

Verification

• yarn test:browser — 131 passed / 2 skipped (~12.8s).
• yarn test:node blocked locally by missing @aztec/bb.js artifact (transitive dep, pre-existing env limitation, unrelated to this fix). The failing CI step timed out in the browser half before node tests started.

Full analysis: https://gist.github.com/AztecBot/c2e5ab8c838332ed915529db81d3f442

Related

• PR fix(kv-store): gate flaky sqlite-opfs browser tests behind VITE_SQLITE_OPFS=1 #22693 — parallel fix on merge-train/spartan.
• Commit 01c0ab1db0 feat!: kv-store on SQLite-wasm over OPFS (#22658) — introduces the affected code.

ClaudeBox log: https://claudebox.work/s/8d2f61f686747a33?run=1

ClaudeBox log: https://claudebox.work/s/8d2f61f686747a33?run=1