patches: fix all review issues from Opus core maintainer review

BLOCKERS fixed:
- #1: add missing skip_overlay_scan: label (goto without target)
- #2: move accessibilityLineForIndex: to patch 0002 (used in 0002/0003,
  was defined in 0007 — forward reference crash risk)
- #3: move BOOL singleLineMove to patch 0008 (declared in 0007, unused
  until 0008 — -Werror build failure)

WARNINGS fixed:
- #1: block_input ordering at 5 sites (record_unwind_protect_void must
  come AFTER block_input to avoid unmatched unblock_input on error)
- #2: deduplicate ns_ax_face_is_selected (move to patch 0001, remove
  from patch 0007 where it was duplicated)
- #4: improve childFrameLastBuffer comment (document rename edge case)
- #5: complete ChangeLog for patch 0007 (add 3 missing method entries)
- #6: document lastSelectedWindow/lastRootWindow GC safety in nsterm.h

MINOR fixed:
- #2: wrap ns_zoom_track_completion call in MAC_OS_X_VERSION >= 101000
  guard (consistent with the function definition)
- #3: @cindex Zoom verified present in VoiceOver section (already OK)
- #4: raise line_starts/line_ends bound from 128 to 512 (consistent
  with ns_ax_selected_overlay_text)
- #5: add echo_area_buffer[] lifetime comment referencing xdisp.c

All 9 patches apply cleanly (git apply verified sequentially).

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

@@ -1,4 +1,4 @@
-From ce123c5b0c25467dd6fb6d4a2aeda59687fadefc Mon Sep 17 00:00:00 2001
+From 9c233aa400c2769e1621ec37f326d1e24c0da2df Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
 Date: Sat, 28 Feb 2026 12:58:11 +0100
 Subject: [PATCH 5/9] ns: add interactive span elements for Tab navigation
@@ -14,14 +14,31 @@ elements with an AXPress action that sends a synthetic TAB keystroke.
 (accessibilityChildrenInNavigationOrder): Return cached span array,
 rebuilding lazily when interactiveSpansDirty is set.
 ---
- src/nsterm.m | 293 +++++++++++++++++++++++++++++++++++++++++++++++++++
- 1 file changed, 293 insertions(+)
+ src/nsterm.m | 302 ++++++++++++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 298 insertions(+), 4 deletions(-)
 
 diff --git a/src/nsterm.m b/src/nsterm.m
-index 9e0e317237..d65609cc79 100644
+index 16343f978a..f5e5cea074 100644
 --- a/src/nsterm.m
 +++ b/src/nsterm.m
-@@ -9346,6 +9346,299 @@ - (NSRect)accessibilityFrame
+@@ -8669,12 +8669,12 @@ - (NSRange)accessibilityRangeForPosition:(NSPoint)screenPoint
+     return NSMakeRange (0, 0);
+ 
+   /* Block input to prevent concurrent redisplay from modifying the
+-     glyph matrix while we traverse it.  Use specpdl unwind protection
+-     so block_input is always matched by unblock_input, even if
+-     ensureTextCache triggers a Lisp signal (longjmp).  */
++     glyph matrix while we traverse it.  block_input must come before
++     record_unwind_protect_void (unblock_input) so that the unwind
++     handler is never called without a matching block_input.  */
+   specpdl_ref count = SPECPDL_INDEX ();
+-  record_unwind_protect_void (unblock_input);
+   block_input ();
++  record_unwind_protect_void (unblock_input);
+ 
+   /* Find the glyph row at this y coordinate.  */
+   struct glyph_matrix *matrix = w->current_matrix;
+@@ -9394,6 +9394,300 @@ - (NSRect)accessibilityFrame
  
  @end
  
@@ -248,11 +265,12 @@ index 9e0e317237..d65609cc79 100644
 +       window being deleted between capture and execution.  */
 +    if (!WINDOWP (lwin) || NILP (Fwindow_live_p (lwin)))
 +      return;
-+    /* Use specpdl unwind protection so that block_input is always
-+       matched by unblock_input, even if Fselect_window signals.  */
++    /* block_input must come before record_unwind_protect_void (unblock_input)
++       so the unwind handler is never invoked without a matching block_input,
++       even if Fselect_window signals (longjmp).  */
 +    specpdl_ref count = SPECPDL_INDEX ();
-+    record_unwind_protect_void (unblock_input);
 +    block_input ();
++    record_unwind_protect_void (unblock_input);
 +    record_unwind_current_buffer ();
 +    Fselect_window (lwin, Qnil);
 +    struct window *w = XWINDOW (lwin);