Add app icon and asset support

- clock.png (10x10) set as fap_icon for app browser
- app_icon.png (47x39) compiled as I_app_icon_47x39 asset for in-app use
- Include digital_alarm_clock_icons.h in source

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EYNXvRg4xjHHE9oPH9kYYU

digital_alarm_clock.c

@@ -1,5 +1,6 @@
 #include <furi.h>
 #include <furi_hal.h>
+#include <digital_alarm_clock_icons.h>
 #include <gui/gui.h>
 #include <gui/view_port.h>
 #include <input/input.h>