patches: fix O(position) lag — O(1) fast path in charposForAccessibilityIndex:

charposForAccessibilityIndex: walked composed character sequences
from the start of a visible run to the target AX index.  For a run
covering an entire ASCII buffer, this is O(cursor_position): moving
to line 10,000 requires ~500,000 iterations per call.

The method is called on every SelectedTextChanged notification
response (accessibilityBoundsForRange: from the AX server for cursor
tracking), making cursor movement O(position) in large files.

Fix: when ax_length == length for a run (all characters are single
AX index units — true for all ASCII/Latin text), the charpos offset
is simply ax_idx - run.ax_start.  O(1) instead of O(position).

Multi-byte runs (emoji, CJK, non-BMP) fall back to the sequence walk,
bounded by run length (visible window size), not total buffer size.

patches/0000-ns-integrate-with-macOS-Zoom-for-cursor-tracking.patch

@@ -1,7 +1,7 @@
-From aeab7e4db306049fb543f60cadcaaa346350f77b Mon Sep 17 00:00:00 2001
+From 03a3e77f9ff5f46429964863a2f320e119c0686c Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
 Date: Sat, 28 Feb 2026 22:39:35 +0100
-Subject: [PATCH 1/9] ns: integrate with macOS Zoom for cursor tracking
+Subject: [PATCH 0/8] ns: integrate with macOS Zoom for cursor tracking
 
 Inform macOS Zoom of the text cursor position so the zoomed viewport
 follows keyboard focus in Emacs.