feat: dual external spool support, AMS slot model filtering & pre-population

Backend:
- Add dual external spool support for H2D (vt_tray as list: Ext-L/Ext-R)
- Add cloud filament ID map endpoint (/cloud/filament-id-map)
- Fix RFID spool data erased by periodic AMS updates (skip tag matcher
  for RFID-tagged trays)
- Fix AMS slot config overwrites RFID spool state
- Fix K-profile selection corrupts existing profiles on X1C/P1S
- Resolve K-profiles filament name via cloud filament ID map
- Update print scheduler and usage tracker for dual external spools

Frontend:
- Add printer model filtering to ConfigureAmsSlotModal (cloud/local/builtin
  presets filtered by @BBL model suffix and compatible_printers)
- Add pre-population for configured slots (preset, color, K-profile)
- Add K-Profiles view with accurate filament name resolution
- Internationalize all ConfigureAmsSlotModal strings (en/de/fr/it/ja — 21 keys)
- Add 5 new ConfigureAmsSlotModal tests (model filtering, pre-selection,
  color pre-population, i18n)
- Update PrintersPage for dual external spool rendering

Docs:
- Update CHANGELOG, README, website features, and wiki AMS docs

README.md

@@ -88,7 +88,8 @@ Perfect for remote print farms, traveling makers, or accessing your home printer
 - Resizable printer cards (S/M/L/XL)
 - Skip objects during print
 - AMS slot RFID re-read
-- AMS slot configuration (custom presets, K profiles, color picker)
+- AMS slot configuration (model-filtered presets, K profiles, color picker, pre-population for configured slots)
+- Dual external spool support for H2D (Ext-L / Ext-R)
 - HMS error monitoring with history
 - Print success rates & trends
 - Filament usage tracking