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

backend/tests/unit/services/test_printer_manager.py

@@ -734,23 +734,26 @@ class TestPrinterStateToDict:
         assert result["ams"][0]["tray"][0]["tag_uid"] is None
 
     def test_vt_tray_parsing(self, mock_state):
-        """Verify virtual tray is parsed correctly."""
+        """Verify virtual tray is parsed correctly as a list."""
         mock_state.raw_data = {
-            "vt_tray": {
-                "tray_color": "00FF00",
-                "tray_type": "PETG",
-                "tray_sub_brands": "Generic",
-                "remain": 60,
-                "tag_uid": "VT123",
-            }
+            "vt_tray": [
+                {
+                    "tray_color": "00FF00",
+                    "tray_type": "PETG",
+                    "tray_sub_brands": "Generic",
+                    "remain": 60,
+                    "tag_uid": "VT123",
+                }
+            ]
         }
 
         result = printer_state_to_dict(mock_state)
 
-        assert result["vt_tray"] is not None
-        assert result["vt_tray"]["id"] == 254
-        assert result["vt_tray"]["tray_color"] == "00FF00"
-        assert result["vt_tray"]["tray_type"] == "PETG"
+        assert isinstance(result["vt_tray"], list)
+        assert len(result["vt_tray"]) == 1
+        assert result["vt_tray"][0]["id"] == 254
+        assert result["vt_tray"][0]["tray_color"] == "00FF00"
+        assert result["vt_tray"][0]["tray_type"] == "PETG"
 
     def test_hms_errors_conversion(self, mock_state):
         """Verify HMS errors are converted correctly."""

backend/tests/unit/services/test_spoolman_tracking.py

@@ -99,14 +99,14 @@ class TestBuildAmsTrayLookup:
     def test_external_spool(self):
         raw = {
             "ams": [],
-            "vt_tray": {"tray_uuid": "EXT", "tag_uid": "X", "tray_type": "TPU"},
+            "vt_tray": [{"tray_uuid": "EXT", "tag_uid": "X", "tray_type": "TPU"}],
         }
         lookup = build_ams_tray_lookup(raw)
         assert 254 in lookup
         assert lookup[254]["tray_type"] == "TPU"
 
     def test_empty_external_spool_skipped(self):
-        raw = {"ams": [], "vt_tray": {"tray_type": ""}}
+        raw = {"ams": [], "vt_tray": [{"tray_type": ""}]}
         lookup = build_ams_tray_lookup(raw)
         assert 254 not in lookup
 

backend/tests/unit/test_scheduler_ams_mapping.py

@@ -140,7 +140,7 @@ class TestBuildLoadedFilaments:
         """Should include external spool."""
 
         class MockStatus:
-            raw_data = {"vt_tray": {"tray_type": "TPU", "tray_color": "0000FF"}}
+            raw_data = {"vt_tray": [{"tray_type": "TPU", "tray_color": "0000FF"}]}
 
         result = scheduler._build_loaded_filaments(MockStatus())
         assert len(result) == 1
@@ -466,7 +466,7 @@ class TestBuildLoadedFilamentsTrayInfoIdx:
         """Should extract tray_info_idx from external spool."""
 
         class MockStatus:
-            raw_data = {"vt_tray": {"tray_type": "TPU", "tray_color": "0000FF", "tray_info_idx": "P4d64437"}}
+            raw_data = {"vt_tray": [{"tray_type": "TPU", "tray_color": "0000FF", "tray_info_idx": "P4d64437"}]}
 
         result = scheduler._build_loaded_filaments(MockStatus())
         assert len(result) == 1
@@ -624,7 +624,7 @@ class TestNozzleAwareMapping:
 
         class MockStatus:
             raw_data = {
-                "vt_tray": {"tray_type": "TPU", "tray_color": "0000FF"},
+                "vt_tray": [{"tray_type": "TPU", "tray_color": "0000FF"}],
                 "ams_extruder_map": {"0": 0},
             }
 
@@ -637,7 +637,7 @@ class TestNozzleAwareMapping:
         """External spool extruder_id should be None without ams_extruder_map."""
 
         class MockStatus:
-            raw_data = {"vt_tray": {"tray_type": "TPU", "tray_color": "0000FF"}}
+            raw_data = {"vt_tray": [{"tray_type": "TPU", "tray_color": "0000FF"}]}
 
         result = scheduler._build_loaded_filaments(MockStatus())
         assert len(result) == 1