Consolidates #13744 (CFS filament sync) into this PR per maintainer
request and resyncs with main. Conflicts resolved:
* src/slic3r/GUI/Plater.cpp -- parallel else-if added by both sides
(htCrealityPrint + flashforge_local_api branches); kept both.
* src/slic3r/GUI/PhysicalPrinterDialog.cpp -- both sides added a
host-specific Browse dialog (Creality DNS-SD + Flashforge); kept
both as early-return branches, fall through to BonjourDialog.
* src/slic3r/GUI/PrintHostDialogs.hpp -- parallel class declarations
(CrealityPrintHostSendDialog + FlashforgePrintHostSendDialog);
kept both.
8dfd480c52