app-module events & callstack config, crash diagnostics (#630)

- Apps can specify task stack depth and preferred memory placement in their manifests.
- App identifiers are validated against length and character requirements.
- Crash diagnostics now show the crash cause, reason, fault address, call stack, and program-counter details, with logs saved for review.
- App closing is more consistent across built-in screens. There's now a dedicated function, and the old _emit() function is made private.
- Crash diagnostics no longer display a QR code without a call stack.
- Improved memory allocation for unrestricted requests.

Modules/app-module/source/event.cpp

@@ -120,4 +120,9 @@ error_t app_event_poll(AppEventSubscription* sub, AppEvent* out_event) {
     return try_pop(sub, out_event) ? ERROR_NONE : ERROR_TIMEOUT;
 }
 
+error_t app_event_emit_close(AppInstanceId instance_id) {
+    AppEvent event { .type = APP_EVENT_CLOSE, .timestamp = 0, .result = {} };
+    return app_event_emit(instance_id, &event);
+}
+
 } // extern "C"