Feature/multi printer support (#12)

* Initial implementation of multi-printer support.

* Always show device dropdown and add bambu_diagnose for multi-printer troubleshooting.

* Add multi-AMS support: per-unit snapshot/usage tracking, grouped dashboard panels with real type labels, and dual-nozzle card UX fixes. Fixes a real-world AMS info-code parsing bug found by inspecting live H2C data.

* Add Vortek hotend rack tracking: per-SN registry with slot mapping confirmed against live MQTT capture, plus a fallback for non-inductive nozzles (e.g. H2C's fixed left nozzle) shown read-only without fabricated identity. New dashboard card hides entirely on printers with no Vortek/nozzle-info data at all.

tests/test_vortek_groundwork.py

@@ -0,0 +1,43 @@
+import pytest
+
+from bambu_run.mqtt_client import PrinterState
+from bambu_run.management.commands.bambu_collector import Command, DeviceSession, resolve_printer_device
+from bambu_run.models import PrinterMetrics
+
+
+def test_snapshot_includes_raw_device_payload_for_future_vortek_modeling():
+    raw_device = {
+        "extruder": {"info": [{"id": 0, "temp": 12058720}, {"id": 1, "temp": 11534560}]},
+        "nozzle": {"info": [{"id": 0, "diameter": 0.4}]},
+    }
+    data = {"print": {"device": raw_device, "gcode_state": "IDLE"}}
+
+    state = PrinterState.from_mqtt_data(data)
+    snapshot = state.get_snapshot()
+
+    assert snapshot["vortek_raw"] == raw_device
+
+
+def test_snapshot_vortek_raw_defaults_to_empty_dict_when_no_device_payload():
+    state = PrinterState.from_mqtt_data({"print": {"gcode_state": "IDLE"}})
+    snapshot = state.get_snapshot()
+
+    assert snapshot["vortek_raw"] == {}
+
+
+@pytest.mark.django_db
+def test_collector_persists_vortek_raw_onto_printer_metrics():
+    printer = resolve_printer_device("SERIAL-A", {"name": "H2C", "dev_product_name": "H2C"})
+
+    class FakeClient:
+        def get_snapshot(self):
+            return {"gcode_state": "IDLE", "vortek_raw": {"extruder": {"info": []}}}
+
+    session = DeviceSession(device_id="SERIAL-A", client=FakeClient(), printer=printer)
+
+    cmd = Command()
+    cmd.verbose = False
+    cmd._collect_printer_data(session)
+
+    metric = PrinterMetrics.objects.get(device=printer)
+    assert metric.vortek_raw == {"extruder": {"info": []}}