Add fire alarm support and update firmware version to 1.0.19

- Introduced CONN_ERR_FIRE_ALARM to handle fire alarm conditions in charger control.
- Added CMD_FIRE_ALARM command for external trigger handling in serial control.
- Updated firmware version from 1.0.17 to 1.0.19.
- Integrated fire alarm functionality into the charging loop and command handler.

Core/Src/fire_alarm.c

@@ -0,0 +1,20 @@
+#include "fire_alarm.h"
+
+#include "charger_control.h"
+#include "debug.h"
+#include "serial.h"
+
+static uint8_t fire_alarm_latched = 0;
+
+uint8_t FireAlarm_IsLatched(void) {
+    return fire_alarm_latched;
+}
+
+void FireAlarm_Activate(void) {
+    if (fire_alarm_latched) {
+        return;
+    }
+
+    fire_alarm_latched = 1;
+    log_printf(LOG_ERR, "FIRE ALARM activated\n");
+}