patches: fix O(overlays) performance regression

Performance issue: editing large files (>~10KB, >2000 lines) caused
progressive slowdown regardless of VoiceOver status.

Root causes:
1. ns_zoom_find_overlay_candidate_line: called Foverlays_in on the
   entire visible buffer range on every redisplay when UAZoomEnabled().
   In files with many overlays (font-lock, hl-line, show-paren etc.)
   this was O(overlays) Lisp work per keystroke.

2. postAccessibilityNotificationsForFrame: when ns-accessibility-enabled
   is non-nil, checked BUF_OVERLAY_MODIFF every redisplay. font-lock
   bumps this on every redraw, triggering ns_ax_selected_overlay_text
   (another O(overlays) scan) for non-minibuffer windows.

Fix: Both scans now guard with MINI_WINDOW_P check. Overlay completion
frameworks (Vertico, Icomplete, Ivy) only display candidates in
minibuffer windows --- no completion framework puts selected-face
overlays in normal editing buffers. For non-minibuffer windows both
functions return immediately with zero Lisp calls.

Additionally: ns_zoom_find_child_frame_candidate is skipped when
f->child_frame_list is nil (no child frames = no Corfu popup).

patches/0006-doc-add-VoiceOver-accessibility-section-to-macOS-app.patch

@@ -1,4 +1,4 @@
-From 4c53081f3308316fa6d03172d727876b8c90815c Mon Sep 17 00:00:00 2001
+From 58616020bbd9e088428e7fd76cc28c19c60cbe05 Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
 Date: Sat, 28 Feb 2026 12:58:11 +0100
 Subject: [PATCH 7/9] doc: add VoiceOver accessibility section to macOS