feature: add apple silicon native macOS support (#81)

* feature: add apple silicon native macOS support - #81

* (macos): Fix crash

This fixes a crash when viewing the rear camera

* fix(macos): keep interpolated presentation on main thread

* fix(macos): supply Retro-WFC payload during setup

* perf(windows): compile out flat-memory fallback check

* remove duplicate smoke test

* test(macos): name and focus host platform tests

* fix(macos): validate Retro-WFC payload cache

* fix(payload): preserve staged file access failures

* Limit flat-page checks to variable-page hosts

---------

Co-authored-by: patchzyy <64382339+patchzyy@users.noreply.github.com>

runtime/include/platform/host_platform.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <cstdint>
+#include <filesystem>
+#include <optional>
+#include <string_view>
+
+// Small host-services boundary for functionality that must not leak Win32
+// assumptions into runtime or game code. Guest execution, virtual memory, and
+// cooperative contexts remain outside this layer until dedicated macOS
+// prototypes establish a safe abstraction.
+namespace RuntimePlatform {
+
+std::optional<std::filesystem::path> ExecutableDirectory() noexcept;
+
+// Returns the platform's conventional per-user application-data directory.
+// It does not create the directory, leaving that policy to the caller.
+std::filesystem::path ApplicationDataDirectory(std::string_view applicationName);
+
+// The root for per-run diagnostics. Keeping this here ensures log placement
+// follows the same host convention as configuration and other user data.
+std::filesystem::path LogDirectory(std::string_view applicationName);
+
+uint64_t CurrentProcessId() noexcept;
+
+} // namespace RuntimePlatform