CUB-33: Integrate Moonraker filament usage polling with UsageLog persistence

backend/API/Jobs/FilamentUsageSyncJob.cs

@@ -1,5 +1,6 @@
 using Extrudex.Domain.Interfaces;
 using Extrudex.Infrastructure.Configuration;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
@@ -15,25 +16,30 @@ namespace Extrudex.API.Jobs;
 /// Configuration is bound from the "FilamentUsageSync" section in
 /// appsettings.json. Set Enabled=false to disable without removing
 /// the service registration.
+/// 
+/// Uses an IServiceScopeFactory to resolve scoped dependencies
+/// (IFilamentUsageSyncService, IUsageLogService) on each sync cycle,
+/// avoiding captive-dependency issues from injecting scoped services
+/// into the singleton BackgroundService lifetime.
 /// </summary>
 public class FilamentUsageSyncJob : BackgroundService
 {
-    private readonly IFilamentUsageSyncService _syncService;
+    private readonly IServiceScopeFactory _scopeFactory;
     private readonly FilamentUsageSyncOptions _options;
     private readonly ILogger<FilamentUsageSyncJob> _logger;
 
     /// <summary>
     /// Creates a new FilamentUsageSyncJob.
     /// </summary>
-    /// <param name="syncService">The service that performs the actual sync logic.</param>
+    /// <param name="scopeFactory">Factory for creating DI scopes to resolve scoped services.</param>
     /// <param name="options">Configuration options for polling interval and timeouts.</param>
     /// <param name="logger">Logger for diagnostic output.</param>
     public FilamentUsageSyncJob(
-        IFilamentUsageSyncService syncService,
+        IServiceScopeFactory scopeFactory,
         IOptions<FilamentUsageSyncOptions> options,
         ILogger<FilamentUsageSyncJob> logger)
     {
-        _syncService = syncService;
+        _scopeFactory = scopeFactory;
         _options = options.Value;
         _logger = logger;
     }
@@ -57,8 +63,10 @@ public class FilamentUsageSyncJob : BackgroundService
         while (!stoppingToken.IsCancellationRequested)
         {
             try
-            {
-                var syncedCount = await _syncService.SyncAllAsync(stoppingToken);
+                       {
+                using var scope = _scopeFactory.CreateScope();
+                var syncService = scope.ServiceProvider.GetRequiredService<IFilamentUsageSyncService>();
+                var syncedCount = await syncService.SyncAllAsync(stoppingToken);
 
                 _logger.LogInformation(
                     "Filament usage sync completed — {SyncedCount} printer(s) synced. Next sync in {Interval}",