Align 2.4.0 pin tracking and pupil-based eyes; add sequence and target-field regressions

scripts/test-tracking.sh

@@ -0,0 +1,12 @@
+#!/bin/zsh
+set -euo pipefail
+cd "${0:A:h:h}"
+output_dir=$(mktemp -d /tmp/fcp-beautygirl-tracking-tests.XXXXXX)
+trap 'rm -rf "$output_dir"' EXIT
+# tracking_tests.m imports the implementation; do not link it a second time.
+xcrun clang -fobjc-arc -fmodules -Wall -Wextra -Wno-unused-parameter \
+  -DCI_SILENCE_GL_DEPRECATION -mmacosx-version-min=13.0 \
+  -framework Foundation -framework CoreImage -framework CoreGraphics \
+  -framework CoreMedia -framework Metal -framework Vision -framework ImageIO \
+  tests/tracking_tests.m -o "$output_dir/tracking-tests"
+"$output_dir/tracking-tests"