Add native SwiftUI player and macOS CI

tools/select_simulator.py

@@ -0,0 +1,15 @@
+"""Select an available iPhone from simctl JSON; print a GitHub environment entry."""
+import json
+import sys
+import uuid
+
+with open(sys.argv[1], encoding="utf-8") as stream:
+    runtimes = json.load(stream)["devices"]
+for runtime in sorted(runtimes, reverse=True):
+    if ".iOS-" not in runtime:
+        continue
+    for device in runtimes[runtime]:
+        if device.get("isAvailable") and device.get("name", "").startswith("iPhone"):
+            print("SIMULATOR_ID=" + str(uuid.UUID(device["udid"])))
+            sys.exit(0)
+sys.exit("No available iPhone simulator in selected Xcode runtime.")