Refactor SDL/FreeRTOS implementation to support macOS simulator properly (#653)

- Run SDL from main() and place FreeRTOS in separate thread. This fixes macOS support.
- Updated GitHub Actions to publish macOS simulator build for testing, updated amd64 to x86_64 for consistent naming.

Devices/simulator/Source/drivers/sdl_bridge.cpp

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: Apache-2.0
+#include "sdl_bridge.h"
+#include "sdl_input.h"
+
+#include <tactility/error.h>
+
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+
+namespace {
+
+struct PresentJob {
+    Device* device;
+    void* internal;
+    int32_t x_start;
+    int32_t y_start;
+    int32_t x_end;
+    int32_t y_end;
+    const void* color_data;
+    error_t result;
+};
+
+std::mutex job_mutex;
+std::condition_variable job_ready_cv;
+std::condition_variable job_done_cv;
+bool job_pending = false;
+bool job_done = false;
+PresentJob pending_job;
+
+}
+
+error_t sdl_bridge_present(Device* device, void* internal, int32_t x_start, int32_t y_start, int32_t x_end, int32_t y_end, const void* color_data) {
+    std::unique_lock<std::mutex> lock(job_mutex);
+
+    pending_job = { device, internal, x_start, y_start, x_end, y_end, color_data, ERROR_NONE };
+    job_pending = true;
+    job_done = false;
+    job_ready_cv.notify_one();
+
+    job_done_cv.wait(lock, [] { return job_done; });
+    return pending_job.result;
+}
+
+void sdl_bridge_run_main_loop() {
+    while (true) {
+        sdl_input_pump();
+
+        std::unique_lock<std::mutex> lock(job_mutex);
+        if (job_ready_cv.wait_for(lock, std::chrono::milliseconds(1), [] { return job_pending; })) {
+            PresentJob job = pending_job;
+            lock.unlock();
+
+            job.result = sdl_display_execute_draw_bitmap(job.device, job.internal, job.x_start, job.y_start, job.x_end, job.y_end, job.color_data);
+
+            lock.lock();
+            pending_job.result = job.result;
+            job_pending = false;
+            job_done = true;
+            lock.unlock();
+            job_done_cv.notify_one();
+        }
+    }
+}