Fix macOS overlay binding and subtitle alignment

scripts/build-macos-helper.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# Build macOS window tracking helper binary
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SWIFT_SOURCE="$SCRIPT_DIR/get-mpv-window-macos.swift"
+OUTPUT_DIR="$SCRIPT_DIR/../dist/scripts"
+OUTPUT_BINARY="$OUTPUT_DIR/get-mpv-window-macos"
+
+# Only build on macOS
+if [[ "$(uname)" != "Darwin" ]]; then
+  echo "Skipping macOS helper build (not on macOS)"
+  exit 0
+fi
+
+# Create output directory
+mkdir -p "$OUTPUT_DIR"
+
+# Compile Swift script to binary
+echo "Compiling macOS window tracking helper..."
+swiftc -O "$SWIFT_SOURCE" -o "$OUTPUT_BINARY"
+
+# Make executable
+chmod +x "$OUTPUT_BINARY"
+
+echo "✓ Built $OUTPUT_BINARY"