[BUG] Performance deterioration in draft contexts with many cursors

Version of Kakoune

Kakoune 2026.05.21-7-ge236e42a

Reproducer

• fill the buffer with a lot of lines: exec '10000+oa<esc>'
• compare the performance of exec 'ghr*' with and without -draft

Outcome

the keys executed in a draft context take longer than without, on my machine it takes 2 seconds, while the latter is almost immediate.

Expectations

there should be no performance difference

Additional information

the lag in draft contexts seems to only happen when there are multiple cursors as well. for example, exec ','; exec -draft '%<a-s>ghr*' executes immediately.