beta release v0.2.5.1b6

Beta: K2 Plus filament usage fix

This beta improves Creality K2 Plus / Moonraker print archiving by reading filament usage from the printer's virtual_sdcard.cur_print_data.metadata.filament_used_g data.

Printbuddy now stores correct filament usage, material type, estimated print time, and per-slot filament usage for K2 Plus prints, instead of relying only on filename parsing or missing Moonraker file metadata.

Also includes safeguards to avoid using stale previous-print data when the K2 reports old cur_print_data during a new print.