Add full nozzle rack metrics and per-slot hover cards for H2C printers

Capture 4 additional fields from MQTT nozzle data (max_temp, serial_number,
filament_color, filament_id) and surface them through REST/WebSocket APIs.
Add per-slot hover popover to the NozzleRackCard showing all metrics, filament
color backgrounds on slots, and i18n labels in all 4 locales.

backend/app/api/routes/printers.py

@@ -369,6 +369,10 @@ async def get_printer_status(
             nozzle_diameter=n.get("diameter", ""),
             wear=n.get("wear"),
             stat=n.get("stat"),
+            max_temp=n.get("max_temp", 0),
+            serial_number=n.get("serial_number", ""),
+            filament_color=n.get("filament_color", ""),
+            filament_id=n.get("filament_id", ""),
         )
         for n in (state.nozzle_rack or [])
     ]

backend/app/schemas/printer.py

@@ -153,6 +153,10 @@ class NozzleRackSlot(BaseModel):
     nozzle_diameter: str = ""
     wear: int | None = None
     stat: int | None = None  # Nozzle status (e.g. mounted/docked)
+    max_temp: int = 0  # Max temperature rating °C (0 = not set)
+    serial_number: str = ""  # Nozzle serial number
+    filament_color: str = ""  # RGBA hex ("00000000" = no filament)
+    filament_id: str = ""  # Bambu filament ID
 
 
 class PrintOptionsResponse(BaseModel):

backend/app/services/bambu_mqtt.py

@@ -1757,9 +1757,20 @@ class BambuMQTTClient:
                             "diameter": str(n.get("diameter", "")),
                             "wear": n.get("wear"),
                             "stat": n.get("stat"),
+                            "max_temp": n.get("max_temp", 0),
+                            "serial_number": str(n.get("serial_number", "")),
+                            "filament_color": str(n.get("filament_colour", "")),
+                            "filament_id": str(n.get("filament_id", "")),
                         }
                         for i, n in enumerate(nozzle_info)
                     ]
+                    if not hasattr(self, "_nozzle_rack_logged") and nozzle_info:
+                        self._nozzle_rack_logged = True
+                        logger.info(
+                            "[%s] Nozzle rack raw keys: %s",
+                            self.serial_number,
+                            [list(n.keys()) for n in nozzle_info[:2]],
+                        )
                 for nozzle in nozzle_info:
                     idx = nozzle.get("id", 0)
                     if idx < len(self.state.nozzles):

backend/app/services/printer_manager.py

@@ -648,7 +648,21 @@ def printer_state_to_dict(state: PrinterState, printer_id: int | None = None, mo
         # Active extruder for dual-nozzle printers (0=right, 1=left)
         "active_extruder": state.active_extruder,
         # H2C nozzle rack (tool-changer dock positions)
-        "nozzle_rack": state.nozzle_rack or [],
+        # Map raw MQTT field names (type/diameter) to schema names (nozzle_type/nozzle_diameter)
+        "nozzle_rack": [
+            {
+                "id": n.get("id", 0),
+                "nozzle_type": n.get("type", ""),
+                "nozzle_diameter": n.get("diameter", ""),
+                "wear": n.get("wear"),
+                "stat": n.get("stat"),
+                "max_temp": n.get("max_temp", 0),
+                "serial_number": n.get("serial_number", ""),
+                "filament_color": n.get("filament_color", ""),
+                "filament_id": n.get("filament_id", ""),
+            }
+            for n in (state.nozzle_rack or [])
+        ],
     }
     # Add cover URL if there's an active print and printer_id is provided
     # Include PAUSE/PAUSED states so skip objects modal can show cover