patches: fix review B1/W1-5 — unwind protection, dealloc leak, DEFSYM nav, lineRange, buffer validation, select-window

B1: setAccessibilitySelectedTextRange: — add record_unwind_protect_void(unblock_input)
    before block_input to prevent permanently blocked input if Fset_marker signals.
W1: EmacsAccessibilityInteractiveSpan — add -dealloc releasing spanLabel/spanValue
    (MRC copy properties leaked on every span rebuild cycle).
W2: ns_ax_event_is_line_nav_key — replace 8x intern_c_string with DEFSYM'd symbols
    (Qns_ax_next_line etc.) to avoid per-cursor-move obarray lookups.
W3: accessibilityRangeForLine: — rewrite from O(n chars) characterAtIndex loop to
    O(lines) lineRangeForRange, matching accessibilityLineForIndex: pattern.
W4: accessibilityChildrenInNavigationOrder — validate buffer before calling
    ns_ax_scan_interactive_spans to prevent Lisp signals in dispatch_sync context.
W5: EmacsAccessibilityBuffer setAccessibilityFocused: — add Fselect_window so
    VoiceOver focus actually switches the Emacs selected window, with proper
    unwind protection for block_input.

patches/README.txt

@@ -2,8 +2,8 @@ EMACS NS VOICEOVER ACCESSIBILITY PATCH
 ========================================
 patch: 0001-ns-implement-AXBoundsForRange-for-macOS-Zoom-cursor-.patch
 author: Martin Sukany <martin@sukany.cz>
-files: src/nsterm.h (+108 lines)
-        src/nsterm.m (+2638 ins, -140 del, +2498 net)
+files: src/nsterm.h (+105 lines)
+        src/nsterm.m (+2844 ins, -149 del, +2695 net)
 
 
 OVERVIEW
@@ -425,12 +425,15 @@ ZOOM INTEGRATION
 KEY DESIGN DECISIONS
 --------------------
 
-  1. DEFSYM instead of intern for property symbols.
+  1. DEFSYM instead of intern for all frequently-used symbols.
      DEFSYM registers symbols at startup (syms_of_nsterm) and stores
-     them in C globals (e.g. Qcompletion__string).  Using intern() at
-     every AX scan would perform an obarray lookup on each redisplay
-     cycle.  DEFSYM symbols are also always reachable by the GC via
-     staticpro, eliminating any risk of premature collection.
+     them in C globals (e.g. Qns_ax_completion__string, Qns_ax_next_line).
+     This covers both property scanning symbols and line navigation
+     command symbols used in ns_ax_event_is_line_nav_key (hot path:
+     runs on every cursor movement).  Using intern() would perform
+     obarray lookups on each redisplay cycle.  DEFSYM symbols are
+     also always reachable by the GC via staticpro, eliminating any
+     risk of premature collection.
 
   2. AnnouncementRequested for character moves, not SelectedTextChanged.
      VoiceOver derives the speech character from SelectedTextChanged by
@@ -503,11 +506,12 @@ KNOWN LIMITATIONS
     covers the common case, but overlay-only changes with a stationary
     point would be missed.  A future fix would compare overlay_modiff.
 
-  - Interactive span scan uses property-change jumps to skip
-    non-interactive regions, but still visits every property boundary.  For
-    large visible buffers this scan runs on every redisplay cycle
-    whenever interactiveSpansDirty is set.  An optimization would use
-    next_single_property_change to skip non-interactive regions in bulk.
+  - Interactive span scan uses Fnext_single_property_change across
+    multiple properties to skip non-interactive regions in bulk, but
+    still visits every property-change boundary.  For buffers with
+    many overlapping text properties (e.g. heavily fontified source
+    code), the number of boundaries can be significant.  The scan
+    runs on every redisplay cycle when interactiveSpansDirty is set.
 
   - Mode line text is extracted from CHAR_GLYPH rows only.  Image
     glyphs, stretch glyphs, and composed glyphs are silently skipped.