Temporarily backport app updates from apps repo

applications/external/mayhem_qrcode/uart_echo.h

@@ -0,0 +1,52 @@
+#include <furi.h>
+#include <furi_hal.h>
+#include <gui/gui.h>
+#include <notification/notification.h>
+#include <notification/notification_messages.h>
+#include <gui/elements.h>
+#include <furi_hal_uart.h>
+#include <furi_hal_console.h>
+#include <gui/view_dispatcher.h>
+#include <gui/modules/dialog_ex.h>
+
+#define LINES_ON_SCREEN 6
+#define COLUMNS_ON_SCREEN 21
+
+typedef struct UartDumpModel UartDumpModel;
+
+typedef struct {
+    Gui* gui;
+    NotificationApp* notification;
+    ViewDispatcher* view_dispatcher;
+    View* view;
+    FuriThread* worker_thread;
+    FuriStreamBuffer* rx_stream;
+    bool initialized;
+} UartEchoApp;
+
+typedef struct {
+    FuriString* text;
+} ListElement;
+
+struct UartDumpModel {
+    ListElement* list[LINES_ON_SCREEN];
+    uint8_t line;
+
+    char last_char;
+    bool escape;
+};
+
+typedef enum {
+    WorkerEventReserved = (1 << 0), // Reserved for StreamBuffer internal event
+    WorkerEventStop = (1 << 1),
+    WorkerEventRx = (1 << 2),
+} WorkerEventFlags;
+
+#define WORKER_EVENTS_MASK (WorkerEventStop | WorkerEventRx)
+
+const NotificationSequence sequence_notification = {
+    &message_display_backlight_on,
+    &message_green_255,
+    &message_delay_10,
+    NULL,
+};