feat(api): add device_type filter to device list endpoint

Operators can now filter the device list by device_type (routeros, snmp)
via ?device_type=snmp query parameter. Enables the frontend type filter.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/routers/devices.py

@@ -91,6 +91,7 @@ async def list_devices(
     sort_order: str = Query("desc", description="asc or desc"),
     site_id: Optional[uuid.UUID] = Query(None, description="Filter by site"),
     sector_id: Optional[uuid.UUID] = Query(None, description="Filter by sector"),
+    device_type: Optional[str] = Query(None, description="Filter by device type (routeros, snmp)"),
     current_user: CurrentUser = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ) -> DeviceListResponse:
@@ -110,6 +111,7 @@ async def list_devices(
         sort_order=sort_order,
         site_id=site_id,
         sector_id=sector_id,
+        device_type=device_type,
     )
     return DeviceListResponse(items=items, total=total, page=page, page_size=page_size)
 

backend/app/services/device.py

@@ -229,6 +229,7 @@ async def get_devices(
     sort_order: str = "desc",
     site_id: Optional[uuid.UUID] = None,
     sector_id: Optional[uuid.UUID] = None,
+    device_type: Optional[str] = None,
 ) -> tuple[list[DeviceResponse], int]:
     """
     Return a paginated list of devices with optional filtering and sorting.
@@ -273,6 +274,9 @@ async def get_devices(
     if sector_id:
         base_q = base_q.where(Device.sector_id == sector_id)
 
+    if device_type:
+        base_q = base_q.where(Device.device_type == device_type)
+
     # Count total before pagination
     count_q = select(func.count()).select_from(base_q.subquery())
     total_result = await db.execute(count_q)