With the 17 life_ patterns there are 66 icons, more than the 64 names the
cache held. It was cleared when full, so every pass over all icons (Icons
tab, page previews) read each one from LittleFS again: /api/icons took
6.5 s and blocked loop() all that time. The cache now holds 128 names and
forgets the missing names first. The sorted icon list is kept until an
icon is saved or deleted. /api/icons: 6.6 s -> 0.12 s.
Version 2.18.2, tested on the display over OTA.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>