Implement posix app loading (#643)

- Added POSIX desktop support for SDK builds, application packaging, and integration testing.
- Added POSIX filesystem partitions and improved application path handling.
- Added simulator support for loading and running applications dynamically.
- Improved simulator task stack handling and display startup reliability.
- Improved simulator display scaling, resizing, high-DPI support, and pointer accuracy.
- Fixed LVGL timers and input polling on POSIX. (fixes simulator with Linux on some Intel graphics platforms)
- Standardized data paths across platforms.
- Logging now works via separate task: this allows apps to write to log without it affecting their stdout (for apps that output text as relevant date for other apps, like the File Selection app)
- Fixes for app stdio

Platforms/platform-posix/source/pthread_stack_wrap.c

@@ -0,0 +1,25 @@
+#include <pthread.h>
+#include <stddef.h>
+
+/**
+ * Linked in with -Wl,--wrap=pthread_attr_setstack (see Tactility/CMakeLists.txt).
+ *
+ * FreeRTOS's POSIX port (Libraries/FreeRTOS-Kernel/portable/ThirdParty/GCC/Posix/port.c)
+ * hands every task a stack carved out of its own heap (pvPortMalloc) via this call.
+ * pthread_attr_setstack requires page alignment, which pvPortMalloc doesn't guarantee;
+ * when it happens to succeed anyway (allocator alignment can vary run to run), the
+ * task's real pthread stack ends up living inside that small FreeRTOS heap region -
+ * fine for typical embedded task code, but a desktop GL driver doing on-the-fly shader
+ * compilation on that thread (e.g. Mesa on first frame present) can overflow it and
+ * silently corrupt adjacent heap_4 objects.
+ *
+ * Wrapping the call out entirely (rather than patching the vendored port.c) leaves every
+ * task's pthread_attr_t at its pthread_attr_init() default, so pthread_create() always
+ * gives it a real, properly allocated default-size stack instead.
+ */
+int __wrap_pthread_attr_setstack(pthread_attr_t* attr, void* stackaddr, size_t stacksize) {
+    (void)attr;
+    (void)stackaddr;
+    (void)stacksize;
+    return 0;
+}