UA1ZBE Custom Firmware v1.0

Features:
- VFO mode with direct frequency input
- POCSAG decoder (512/1200 baud) with BCH(31,21) correction
- Full-screen Spectrum analyzer
- FM Radio receiver
- RSSI signal indicator overlay
- Custom boot splash (UA1ZBE / POCSAG pager / build date)

Architecture:
- app/mode.c — mode dispatcher (VFO/POCSAG/Spectrum/FM)
- app/boot_splash.c — 2-second boot splash
- app/pocsag/ — POCSAG decoder + BCH correction
- app/display_rssi.c — RSSI indicator
- main.c — entry point with custom init
- syscalls.c — bare-metal _sbrk stub

Build: arm-none-eabi-gcc -Os -flto -Wall -Werror -Wextra
Size: 57.9KB Flash / 3.6KB RAM

Controls:
- 0-9: Direct frequency input (VFO)
- SK2: POCSAG mode
- SK1: Spectrum analyzer
- 0: FM Radio
- EXIT: Return to VFO
- F/*: Toggle 512/1200 baud (in POCSAG)

app/flashlight.h

@@ -0,0 +1,23 @@
+#ifndef APP_FLASHLIGHT_H
+#define APP_FLASHLIGHT_H
+
+#ifdef ENABLE_FLASHLIGHT
+
+#include <stdint.h>
+
+enum FlashlightMode_t {
+    FLASHLIGHT_OFF = 0,
+    FLASHLIGHT_ON,
+    FLASHLIGHT_BLINK,
+    FLASHLIGHT_SOS
+};
+
+extern enum FlashlightMode_t gFlashLightState;
+extern volatile uint16_t     gFlashLightBlinkCounter;
+
+void FlashlightTimeSlice(void);
+void ACTION_FlashLight(void);
+
+#endif
+
+#endif