#662's test queued three keys and read them all after one poll; #628 (for #625,
keys typing twice) reads one key per poll and drops the same key again within
70 ms. The test now polls per key and also checks that a repeat inside 70 ms is
dropped and one after it is a new press. Host tests: 18 pass, 2 skips.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>