FTP upload: reduce chunk size from 1MB to 64KB for smooth progress bar
updates (~1s intervals instead of 20+ second gaps). Skip voidresp() for
all printer models — H2D delays the 226 response by 30+ seconds after
data transfer, causing a hang at 100%. Add transfer speed and TLS
handshake timing to logs for diagnosing slow connections.
Print/Schedule modal: widen from max-w-lg (512px) to max-w-2xl (672px)
to accommodate long filament profile names like "PLA Support for PETG
PETG Basic @Bambu Lab H2D 0.4 nozzle".