Add ECC support for Nvidia professional GPUs

[LH-and-FPGA]

Summary

Adds an ECC error counter to the device header, shown right after the power field. NVIDIA professional and datacenter GPUs (e.g. RTX PRO, Quadro, Tesla, A100/H100) expose volatile ECC error counts through NVML; this surfaces them in nvtop.

Display format is ECC <corrected>/<uncorrected>:

• corrected — single-bit errors automatically fixed by ECC (normal)
• uncorrected — double-bit errors; a non-zero value is highlighted in red since it indicates a hardware fault

The field follows the existing "valid bit" pattern: on GPUs that do not support ECC (consumer cards, older drivers), NVML return NVML_ERROR_NOT_SUPPORTED, the valid bit stays unset, and the field is simply left blank — no special-casing required.

Changes

• extract_gpuinfo_common.h: add ecc_corrected / ecc_uncorrected dynamic fields and their valid bits
• extract_gpuinfo_nvidia.c: load nvmlDeviceGetTotalEccErrors (optional symbol, so older NVML libs still work) and query volatile ECC counts
• interface.c / interface_internal_common.h: add the ecc_info window and draw it after the power field

Notes

• Volatile counters are used (errors since last driver reload/reboot).
• Tested on a machine with an RTX PRO 4000 Blackwell (ECC enabled, shows ECC 0/0) and an RTX 5090 (no ECC, field correctly hidden).