testcafe-0001: Selector filterNodes (string-filter branch) and
expandSelectorResults both dedup via Array.indexOf on growing result
arrays. filterNodes: O(N*M) per selector filter. expandSelectorResults:
O(N^2 * K^2) worst case when derivatives unique. Fix: Set<Node> keyed
by object identity. Bench: 398x at N=2000 filter, 1966x at N=K=150
expand.
webdriverio-0002: MSPO aggregator dedups per-test entries via Array.find
on growing bucket array. O(N^2) per test bucket, same pattern repeats
in unknown-suite merger. Fix: companion Map<bucketKey, Set<selector>>
for O(1) dedup. Bench: 493x at N=2000.
UNDF IDs: 1290 (testcafe), 1291 (webdriverio-0002). All 17 tests pass.