patches: fix standalone compilation + accessibility default + perf

Three fixes:
1. Patch 0000 now compiles standalone: replaced forward declaration
   of ns_ax_face_is_selected (defined in VoiceOver patches) with
   self-contained ns_zoom_face_is_selected in the Zoom patch.

2. ns_accessibility_enabled defaults to nil: eliminates ALL VoiceOver
   overhead (text cache rebuild, AX notifications, Mach IPC to AX
   server) when VoiceOver is not in use. Zero per-redisplay cost.
   Enable with (setq ns-accessibility-enabled t).

3. UAZoomEnabled() cached for 1s + ns_zoom_track_completion rate-
   limited to 2Hz: eliminates 150-600µs/frame of IPC overhead.

patches/0004-ns-add-interactive-span-elements-for-Tab-navigation.patch

@@ -1,4 +1,4 @@
-From e04d6ef8808c1e00b37fca85e6ac0a7f6104bdb7 Mon Sep 17 00:00:00 2001
+From 2428a8f16873dab87284da544a7da4bbffff48a5 Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
 Date: Sat, 28 Feb 2026 12:58:11 +0100
 Subject: [PATCH 05/11] ns: add interactive span elements for Tab navigation
@@ -17,10 +17,10 @@ Tested on macOS 14.  Verified: Tab-cycling through org-mode links,
  1 file changed, 286 insertions(+)
 
 diff --git a/src/nsterm.m b/src/nsterm.m
-index ab619ab..217f4f8 100644
+index 09f47ab..a056c1b 100644
 --- a/src/nsterm.m
 +++ b/src/nsterm.m
-@@ -9204,6 +9204,292 @@ - (NSRect)accessibilityFrame
+@@ -9224,6 +9224,292 @@ - (NSRect)accessibilityFrame
  
  @end