feat(modbus): Add supply voltage register and display in tool

This commit introduces a new Modbus input register for the system's supply voltage.

- The `modbus-registers.de.md` documentation is updated to include the `SUPPLY_VOLTAGE_MV` register at address `0x00F5` within the system block.
- The `modbus_server.h` header defines the new register.
- The `modbus_server.c` implementation provides a fixed value (12300 mV) for this register.
- The `modbus_tool.py` script is updated to read and display this new supply voltage value in the UI.

This lays the groundwork for integrating actual voltage measurements in the future.

software/include/lib/modbus_server.h

@@ -6,42 +6,44 @@
 /**
  * @brief Modbus Input Register Addresses.
  */
-enum {
+enum
+{
 	/* Valve Control & Status */
-	REG_INPUT_VALVE_STATE_MOVEMENT        = 0x0000,
-	REG_INPUT_MOTOR_CURRENT_MA            = 0x0001,
+	REG_INPUT_VALVE_STATE_MOVEMENT = 0x0000,
+	REG_INPUT_MOTOR_CURRENT_MA = 0x0001,
 	/* Digital Inputs */
-	REG_INPUT_DIGITAL_INPUTS_STATE        = 0x0020,
-	REG_INPUT_BUTTON_EVENTS               = 0x0021,
+	REG_INPUT_DIGITAL_INPUTS_STATE = 0x0020,
+	REG_INPUT_BUTTON_EVENTS = 0x0021,
 	/* System Config & Status */
 	REG_INPUT_FIRMWARE_VERSION_MAJOR_MINOR = 0x00F0,
-	REG_INPUT_FIRMWARE_VERSION_PATCH      = 0x00F1,
-	REG_INPUT_DEVICE_STATUS               = 0x00F2,
-	REG_INPUT_UPTIME_SECONDS_LOW          = 0x00F3,
-	REG_INPUT_UPTIME_SECONDS_HIGH         = 0x00F4,
-	/* Firmware Update */
-	REG_INPUT_FWU_LAST_CHUNK_CRC          = 0x0100,
+	REG_INPUT_FIRMWARE_VERSION_PATCH = 0x00F1,
+	REG_INPUT_DEVICE_STATUS = 0x00F2,
+	REG_INPUT_UPTIME_SECONDS_LOW = 0x00F3,
+	REG_INPUT_UPTIME_SECONDS_HIGH = 0x00F4,
+	REG_INPUT_SUPPLY_VOLTAGE_MV = 0x00F5,
+	REG_INPUT_FWU_LAST_CHUNK_CRC = 0x0100
 };
 
 /**
  * @brief Modbus Holding Register Addresses.
  */
-enum {
+enum
+{
 	/* Valve Control */
-	REG_HOLDING_VALVE_COMMAND             = 0x0000,
-	REG_HOLDING_MAX_OPENING_TIME_S        = 0x0001,
-	REG_HOLDING_MAX_CLOSING_TIME_S        = 0x0002,
+	REG_HOLDING_VALVE_COMMAND = 0x0000,
+	REG_HOLDING_MAX_OPENING_TIME_S = 0x0001,
+	REG_HOLDING_MAX_CLOSING_TIME_S = 0x0002,
 	/* Digital Outputs */
-	REG_HOLDING_DIGITAL_OUTPUTS_STATE     = 0x0010,
+	REG_HOLDING_DIGITAL_OUTPUTS_STATE = 0x0010,
 	/* System Config */
-	REG_HOLDING_WATCHDOG_TIMEOUT_S        = 0x00F0,
-	REG_HOLDING_DEVICE_RESET              = 0x00F1,
+	REG_HOLDING_WATCHDOG_TIMEOUT_S = 0x00F0,
+	REG_HOLDING_DEVICE_RESET = 0x00F1,
 	/* Firmware Update */
-	REG_HOLDING_FWU_COMMAND               = 0x0100,
-	REG_HOLDING_FWU_CHUNK_OFFSET_LOW      = 0x0101,
-	REG_HOLDING_FWU_CHUNK_OFFSET_HIGH     = 0x0102,
-	REG_HOLDING_FWU_CHUNK_SIZE            = 0x0103,
-	REG_HOLDING_FWU_DATA_BUFFER           = 0x0180,
+	REG_HOLDING_FWU_COMMAND = 0x0100,
+	REG_HOLDING_FWU_CHUNK_OFFSET_LOW = 0x0101,
+	REG_HOLDING_FWU_CHUNK_OFFSET_HIGH = 0x0102,
+	REG_HOLDING_FWU_CHUNK_SIZE = 0x0103,
+	REG_HOLDING_FWU_DATA_BUFFER = 0x0180,
 };
 
 int modbus_server_init(void);