The parseKeypress kitty query-response filter (ESC[?Nu -> {ignore:true}, dropped by useInput)
was assumed to be a redundant second net duplicating the upstream kitty-keyboard detection
strip. Verified it is NOT redundant: the upstream strip runs only in the one-shot
confirmKittySupport detection listener (a private buffer), not on the steady-state input path
(stdin 'data' -> inputParser -> emitInput -> useInput -> parseKeypress). Removing the filter
leaks a stray query-response to handlers as spurious "[?1u" input in enabled mode, auto mode,
and split delivery (inputParser reassembles, so the upstream partial-handling doesn't apply).
Ink has the same gap (its parse-keypress has no query filter; its steady-state input uses
'readable', not 'data').
Keeps the filter (adds a why-comment) and records it as an additive divergence in
ink-divergences.md. Adds 4 end-to-end regression tests proving the filter is load-bearing.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Yunfei He
8e14081a7c