patches: review fixes — defvar, method extraction, GC safety, window_end_valid

Review-based improvements:
- ns-accessibility-enabled DEFVAR_BOOL (disable AX overhead)
- window_end_valid guard in ns_ax_window_end_charpos
- GC safety comments on Lisp_Object ObjC ivars
- postAccessibilityNotificationsForFrame split into 4 methods
- block_input in ns_ax_completion_text_for_span
- Fplist_get predicate comment
- macos.texi VoiceOver section with defvar docs
- README updated with USER OPTION + REVIEW CHANGES sections

patches/0002-doc-add-VoiceOver-accessibility-section-to-macOS-app.patch

@@ -1,24 +1,24 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From ce3b2a8091c99f738ec59acd6f6ebf0d84826e34 Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
-Date: Fri, 27 Feb 2026 17:30:00 +0100
+Date: Fri, 27 Feb 2026 17:49:51 +0100
 Subject: [PATCH 2/2] doc: add VoiceOver accessibility section to macOS
  appendix
 
 Document the new VoiceOver accessibility support in the Emacs manual.
 Add a new section to the macOS appendix covering screen reader usage,
-keyboard navigation feedback, completion announcements, and Zoom
-cursor tracking.
+keyboard navigation feedback, completion announcements, Zoom cursor
+tracking, and the ns-accessibility-enabled user option.
 
 * doc/emacs/macos.texi (VoiceOver Accessibility): New section.
 ---
- doc/emacs/macos.texi | 46 +++++++++++++++++++++++++++++++++++++++++++
- 1 file changed, 46 insertions(+)
+ doc/emacs/macos.texi | 53 ++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 53 insertions(+)
 
 diff --git a/doc/emacs/macos.texi b/doc/emacs/macos.texi
-index 1234567..abcdefg 100644
+index 6bd334f..1d969f9 100644
 --- a/doc/emacs/macos.texi
 +++ b/doc/emacs/macos.texi
-@@ -31,6 +31,7 @@ Support}), but we hope to improve it in the future.
+@@ -36,6 +36,7 @@ Support}), but we hope to improve it in the future.
  * Mac / GNUstep Basics::        Basic Emacs usage under GNUstep or macOS.
  * Mac / GNUstep Customization:: Customizations under GNUstep or macOS.
  * Mac / GNUstep Events::        How window system events are handled.
@@ -26,10 +26,10 @@ index 1234567..abcdefg 100644
  * GNUstep Support::             Details on status of GNUstep support.
  @end menu
  
-@@ -272,6 +273,51 @@ services and receive the results back.  Note that you may need to
+@@ -272,6 +273,58 @@ and return the result as a string.  You can also use the Lisp function
+ services and receive the results back.  Note that you may need to
  restart Emacs to access newly-available services.
  
- 
 +@node VoiceOver Accessibility
 +@section VoiceOver Accessibility (macOS)
 +@cindex VoiceOver
@@ -70,6 +70,12 @@ index 1234567..abcdefg 100644
 +position is communicated via @code{UAZoomChangeFocus} and the
 +@code{AXBoundsForRange} accessibility attribute.
 +
++@vindex ns-accessibility-enabled
++  To disable the accessibility interface entirely (for instance, to
++eliminate overhead on systems where assistive technology is not in
++use), set @code{ns-accessibility-enabled} to @code{nil}.  The default
++is @code{t}.
++
 +  This support is available only on the Cocoa build; GNUstep has a
 +different accessibility model and is not yet supported
 +(@pxref{GNUstep Support}).  Evil-mode block cursors are handled
@@ -81,3 +87,4 @@ index 1234567..abcdefg 100644
  
 -- 
 2.43.0
+