BambuStudio converts virtual tray IDs (254/255) to -1 in the flat
ams_mapping and relies on ams_mapping2 for external spool routing.
Bambuddy was passing raw 254/255 in the flat array, which H2D firmware
rejects with "Failed to get AMS mapping table".
- Convert external tray IDs to -1 in flat ams_mapping (match BambuStudio)
- Fix ams_mapping2 for external trays: each virtual tray is its own AMS
unit with slot_id 0, not a shared unit differentiated by slot
- Fix main/deputy nozzle ID comment (255=main, 254=deputy per BambuStudio)
- Add 8 unit tests for start_print() mapping construction
maziggy
5926e722f8