- rank.test.ts: 100-iteration zipper mid-point insert precision test (Pitfall 2);
rank-between-neighbors contract test; total 10 tests (was 8)
- lists.test.ts: 5 new LIST-03 ordering tests — PATCH position updates only rank
and GET returns new ASC order; one-row write asserts other items unchanged;
LWW (D-15): second PATCH overwrites first; T-04-07 two-field position PATCH → 400
- Note: tests use a0–a5 rank range (avoids uppercase ranks that sort differently
under MariaDB utf8mb4_unicode_ci vs JS lexicographic order)