fix: error-status data written to different files than normal data

[k-rister]

Bugs Found

1. Error rows written to wrong file path (HIGH)

mlxreg-collect lines 59/69 vs 81/86: Error rows use ${device//://} (replaces colons with /) creating nested subdirectories, while normal rows use ${device//:} (removes colons). Error data goes to completely different file paths than normal data, breaking data continuity.

2. Default sensors don't match documentation (MEDIUM)

mlxreg-start line 11: Default sensors are 1,2,6,127 but README documents only 1,2,6.

3. Wrong CDM metric class (MEDIUM)

mlxreg-post-process line 87: CDM metric class is count but should be power for power measurements.