VDF750 Configurator 2.7.0

Added dedicated CAN Master/Slave diagnostics tab:
- reads Master U0-63 (point-to-point TX) and Slave U0-64 (point-to-point RX)
- simultaneous charts for CAN TX/RX, Delta CAN, frequency, torque, current and DC bus
- diagnostic counters for Err16 and PC/Modbus polling misses
- timestamped event log with Err16 appearance/recovery and Slave polling loss/recovery
- optional diagnostic CSV recording
- reads and compares PD-00 CAN baud code, PD-08 and A8-00/A8-01/A8-02/A8-03/A8-06/A8-07
- warnings for mismatched CAN baud, incorrect Master/Slave roles and unsafe timing relationship
- automatic diagnostic hints for Err16, TX/RX mismatch and monitoring gaps
- fixed signed interpretation for U0-63/U0-64 and torque-related signed values
- reads extended U0-59..U0-65 block where firmware supports it

Important distinction:
The software cannot observe raw CAN frames through the RS-485 configurator connection. "Slave sample gap" and "missed polls" refer to PC-to-drive Modbus diagnostic polling. CANlink health is inferred/correlated from U0-63/U0-64, drive fault status and CANlink configuration/timeouts.
