fix(ams): derive setting_id when configuring a built-in filament on a slot (#2604)

The Configure AMS Slot modal sends built-in / local / Orca-generic presets
with a GF* tray_info_idx but an empty setting_id, and configure_ams_slot
forwarded that empty value to ams_filament_setting. The firmware treats a
filament-id-without-setting-id slot as half configured: it shows the new
material briefly, then reverts to its previously stored profile.

Back-fill setting_id from the resolved tray_info_idx via
filament_id_to_setting_id when the client sent none (e.g. GFB99 -> GFSB99),
mirroring the derivation the inventory/assignment path already does. Doing
it server-side also protects API callers and future frontends. P* user
presets and already-GFS* values are left unchanged, and an explicit
setting_id still passes through untouched.

backend/app/api/routes/printers.py

@@ -61,6 +61,7 @@ from backend.app.services.printer_manager import (
     supports_drying,
     supports_drying_while_printing,
 )
+from backend.app.utils.filament_ids import filament_id_to_setting_id
 from backend.app.utils.http import build_content_disposition
 
 logger = logging.getLogger(__name__)
@@ -2447,6 +2448,18 @@ async def configure_ams_slot(
         if kprofile_setting_id:
             effective_setting_id = kprofile_setting_id
 
+    # Back-fill setting_id from the resolved filament id when the client sent
+    # none. Built-in / local / Orca-generic presets in the Configure AMS Slot
+    # modal leave setting_id empty (they carry only a GF* tray_info_idx), and
+    # the printer treats a filament-id-without-setting-id slot as half
+    # configured: it shows the new material briefly, then reverts to its
+    # previously stored profile (#2604). This mirrors the derivation the
+    # inventory/assignment path already does (inventory.py). filament_id_to_
+    # setting_id leaves P* user presets and already-GFS* values unchanged, so
+    # only the empty-setting_id generic paths are affected.
+    if effective_tray_info_idx and not effective_setting_id:
+        effective_setting_id = filament_id_to_setting_id(effective_tray_info_idx)
+
     # Always send ams_set_filament_setting — the user explicitly clicked
     # "Configure Slot", so honor that.  Previous versions skipped this for
     # RFID-tagged slots to preserve the slicer eye icon, but printers cache

backend/tests/integration/test_printers_api.py

@@ -1130,6 +1130,82 @@ class TestConfigureAMSSlotAPI:
             call_kwargs = mock_client.ams_set_filament_setting.call_args
             assert call_kwargs.kwargs["tray_info_idx"] == "GFL05"
 
+    @pytest.mark.asyncio
+    @pytest.mark.integration
+    async def test_configure_builtin_empty_setting_id_is_derived(self, async_client: AsyncClient, printer_factory):
+        """A built-in preset (GF* tray_info_idx, empty setting_id) gets a derived GFS* setting_id (#2604).
+
+        The Configure AMS Slot modal sends built-in / local / Orca-generic presets with an
+        empty setting_id. Publishing a filament-id-without-setting-id slot makes the printer
+        treat it as half configured and revert to its previous profile, so the route must
+        back-fill setting_id from the resolved tray_info_idx.
+        """
+        printer = await printer_factory(name="X1C")
+
+        mock_client = MagicMock()
+        mock_client.ams_set_filament_setting.return_value = True
+        mock_client.extrusion_cali_sel.return_value = True
+        mock_client.request_status_update.return_value = True
+
+        with patch("backend.app.api.routes.printers.printer_manager") as mock_pm:
+            mock_pm.get_client.return_value = mock_client
+            mock_pm.get_status.return_value = None
+
+            response = await async_client.post(
+                f"/api/v1/printers/{printer.id}/slots/0/1/configure",
+                params={
+                    "tray_info_idx": "GFB99",  # Generic ABS, built-in
+                    "tray_type": "ABS",
+                    "tray_sub_brands": "Generic ABS",
+                    "tray_color": "000000FF",
+                    "nozzle_temp_min": 240,
+                    "nozzle_temp_max": 280,
+                    # setting_id intentionally omitted (empty) — as the modal sends it
+                },
+            )
+
+            assert response.status_code == 200
+            call_kwargs = mock_client.ams_set_filament_setting.call_args
+            assert call_kwargs.kwargs["tray_info_idx"] == "GFB99"
+            assert call_kwargs.kwargs["setting_id"] == "GFSB99"
+
+    @pytest.mark.asyncio
+    @pytest.mark.integration
+    async def test_configure_generic_material_fallback_derives_setting_id(
+        self, async_client: AsyncClient, printer_factory
+    ):
+        """When only a material is given, the generic tray_info_idx fallback still yields a setting_id (#2604)."""
+        printer = await printer_factory(name="X1C")
+
+        mock_client = MagicMock()
+        mock_client.ams_set_filament_setting.return_value = True
+        mock_client.extrusion_cali_sel.return_value = True
+        mock_client.request_status_update.return_value = True
+
+        mock_status = MagicMock()
+        mock_status.raw_data = {"ams": {"ams": []}}  # No existing tray to reuse
+
+        with patch("backend.app.api.routes.printers.printer_manager") as mock_pm:
+            mock_pm.get_client.return_value = mock_client
+            mock_pm.get_status.return_value = mock_status
+
+            response = await async_client.post(
+                f"/api/v1/printers/{printer.id}/slots/0/1/configure",
+                params={
+                    "tray_info_idx": "",  # No preset id — route derives generic from material
+                    "tray_type": "ABS",
+                    "tray_sub_brands": "Generic ABS",
+                    "tray_color": "000000FF",
+                    "nozzle_temp_min": 240,
+                    "nozzle_temp_max": 280,
+                },
+            )
+
+            assert response.status_code == 200
+            call_kwargs = mock_client.ams_set_filament_setting.call_args
+            assert call_kwargs.kwargs["tray_info_idx"] == "GFB99"
+            assert call_kwargs.kwargs["setting_id"] == "GFSB99"
+
     @pytest.mark.asyncio
     @pytest.mark.integration
     async def test_configure_pfus_sent_directly(self, async_client: AsyncClient, printer_factory):