feat: Implement Discord app UI and settings management

- Added MainUI class for displaying voice state, status icon, and buttons.
- Introduced MainUIHandler to manage UI interactions and bridge communication.
- Created SettingsUI for displaying QR code and configuration instructions.
- Implemented SettingsUIHandler to manage settings and web server interactions.
- Developed WebHandler for handling HTTP requests for settings configuration.
- Updated AppRegistry to initialize with the new Discord app descriptor.
- Enhanced InteractionHandler to support keyboard interactions across app switches.
- Updated UIHandler to manage app switching and rendering of app icons.
- Enabled QR code support in LVGL configuration.

main/ui/apps/iotdis/descriptor.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "ui/apps/app.h"
+#include "ui/apps/iotdis/app.h"
+
+class IotDisDescriptor : public AppDescriptor {
+public:
+  IotDisDescriptor();
+  ~IotDisDescriptor() override = default;
+
+  void draw_icon(lv_obj_t* parent) override;
+};