0.1.8: media_kit hot-restart guard (Linux, debug)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

linux/include/fox_utils/media_kit_restart_guard.h

@@ -0,0 +1,15 @@
+// Debug builds only: keeps a Flutter hot restart from crashing apps that use
+// media_kit on Linux. Hot restart frees the old isolate's NativeCallables
+// while mpv handles stay alive; media_kit then "quit"s the leftovers and mpv
+// calls a dead wakeup callback (SIGSEGV on mpv's "core" thread). On the
+// engine's on-pre-engine-restart signal this clears every live handle's
+// wakeup callback (found through media_kit's NativeReferenceHolder file).
+// Does nothing without media_kit/libmpv, and nothing in release builds.
+#ifndef FOX_UTILS_MEDIA_KIT_RESTART_GUARD_H_
+#define FOX_UTILS_MEDIA_KIT_RESTART_GUARD_H_
+
+#include <flutter_linux/flutter_linux.h>
+
+void media_kit_restart_guard_register_with_registrar(FlPluginRegistrar* registrar);
+
+#endif