After configuring an AMS-HT slot with a custom cloud preset, the slot
card and Configure modal kept showing "Generic PLA" even though the
printer and slicer had the correct preset. The `/slot-presets` response
keyed HT entries at `ams_id * 4 + tray_id = 512`, but frontend lookups
used `ams_id` directly (128 on PrintersPage via getGlobalTrayId, 64 on
SpoolBuddy via a one-off formula). All three agreed for regular AMS, so
the mismatch only surfaced on HT — the saved preset never reached the
UI and the render fell through to `tray.tray_type`.
Backend now keys via a helper that mirrors frontend `getGlobalTrayId`.
SpoolBuddy's AMS page switches to the shared helper. Regression test
covers regular, HT, and external slot keys.
maziggy
87a5aa36e9