Add H2C dual-nozzle and multi-AMS-type support

Schema (migration 0004):
- PrinterMetrics: nozzle_temp_left, nozzle_target_temp_left,
  nozzle_diameter_left, nozzle_type_left (all nullable)
- Filament: ams_unit_id (nullable int), ams_type (AMS/AMS 2 Pro/AMS HT)
- AMS_INFO_TO_TYPE map and AMS_TYPE_CHOICES on models

Parser (mqtt_client.py):
- Decode bit-packed temps from device.extruder.info[] for left/right nozzle
- Emit per-nozzle fields in get_snapshot(); legacy keys mirror right side
- AMS unit type from info code per unit dict

Collector (bambu_collector.py):
- Write left-nozzle fields to PrinterMetrics
- Set ams_unit_id + ams_type on Filament records
- Fix: poll MQTTClient.connected before pushall (not BambuPrinter._connected)
- Add 5s post-pushall wait in --once mode so response arrives before collect

Views: API and dashboard include left-nozzle series; is_dual_nozzle flag
Templates: dual-nozzle cards + chart; AMS-type badge + filter on filament list
Charts: left nozzle temp chart with conditional render
Forms: fix tray_id max=3 → max=15; add ams_unit_id, ams_type fields

bambu_run/forms.py

@@ -55,7 +55,7 @@ class FilamentForm(forms.ModelForm):
             'filament_type', 'type', 'sub_type', 'brand', 'color', 'color_hex', 'is_transparent',
             'diameter', 'initial_weight_grams',
             'remaining_percent', 'remaining_weight_grams',
-            'is_loaded_in_ams', 'current_tray_id',
+            'is_loaded_in_ams', 'current_tray_id', 'ams_unit_id', 'ams_type',
             'purchase_date', 'purchase_price', 'supplier', 'notes'
         ]
         widgets = {
@@ -87,7 +87,15 @@ class FilamentForm(forms.ModelForm):
             'remaining_weight_grams': forms.NumberInput(attrs={'class': 'form-control', 'readonly': 'readonly'}),
             'is_transparent': forms.CheckboxInput(attrs={'class': 'form-check-input', 'id': 'id_is_transparent'}),
             'is_loaded_in_ams': forms.CheckboxInput(attrs={'class': 'form-check-input'}),
-            'current_tray_id': forms.NumberInput(attrs={'class': 'form-control', 'min': '0', 'max': '3'}),
+            'current_tray_id': forms.NumberInput(attrs={
+                'class': 'form-control', 'min': '0', 'max': '15',
+                'placeholder': '0–3 for AMS / AMS 2 Pro, 0 for AMS HT',
+            }),
+            'ams_unit_id': forms.NumberInput(attrs={
+                'class': 'form-control', 'min': '0', 'max': '255',
+                'placeholder': 'AMS unit id (0,1,… or 128 for AMS HT)',
+            }),
+            'ams_type': forms.Select(attrs={'class': 'form-select'}),
             'purchase_date': forms.DateInput(attrs={'class': 'form-control', 'type': 'date'}),
             'purchase_price': forms.NumberInput(attrs={'class': 'form-control', 'step': '0.01'}),
             'supplier': forms.TextInput(attrs={'class': 'form-control'}),
@@ -106,6 +114,8 @@ class FilamentForm(forms.ModelForm):
         self.fields['type'].required = False
         self.fields['sub_type'].required = False
         self.fields['brand'].required = False
+        self.fields['ams_unit_id'].required = False
+        self.fields['ams_type'].required = False
 
         self._populate_color_choices()