fix: PlatformHttpClientFactory uses IServiceScopeFactory to avoid disposed DbContext in danmaku retry

PlatformHttpClientFactory was holding a direct ISystemSettingsService reference
(Scoped). When the danmaku connection's request scope ended, retry attempts failed
with ObjectDisposedException on LiveRecorderDbContext.

Changed to use IServiceScopeFactory to create a fresh scope on each CreateAsync call,
so the danmaku retry loop always gets a live DbContext.

Co-Authored-By: Claude Opus 4.8 noreply@anthropic.com

src/LiveRecorder.Infrastructure/Services/PlatformHttpClientFactory.cs

@@ -5,6 +5,7 @@ using LiveRecorder.Application.Common;
 using LiveRecorder.Application.Abstractions.Settings;
 using LiveRecorder.Application.Models.Settings;
 using LiveRecorder.Domain.Enums;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace LiveRecorder.Infrastructure.Services;
 
@@ -13,11 +14,11 @@ public sealed class PlatformHttpClientFactory
     private static readonly TimeSpan DefaultTimeout = TimeSpan.FromSeconds(20);
     private static readonly TimeSpan DefaultConnectTimeout = TimeSpan.FromSeconds(10);
 
-    private readonly ISystemSettingsService _systemSettingsService;
+    private readonly IServiceScopeFactory _serviceScopeFactory;
 
-    public PlatformHttpClientFactory(ISystemSettingsService systemSettingsService)
+    public PlatformHttpClientFactory(IServiceScopeFactory serviceScopeFactory)
     {
-        _systemSettingsService = systemSettingsService;
+        _serviceScopeFactory = serviceScopeFactory;
     }
 
     public async Task<HttpClient> CreateAsync(
@@ -25,7 +26,9 @@ public sealed class PlatformHttpClientFactory
         bool forceDirectConnection,
         CancellationToken cancellationToken = default)
     {
-        var settings = await _systemSettingsService.GetAsync(cancellationToken);
+        using var scope = _serviceScopeFactory.CreateScope();
+        var systemSettingsService = scope.ServiceProvider.GetRequiredService<ISystemSettingsService>();
+        var settings = await systemSettingsService.GetAsync(cancellationToken);
         var proxy = forceDirectConnection ? null : BuildProxy(platform, settings);
         var handler = new SocketsHttpHandler
         {