v0.19.0 — Bump default parallel segments 8→16 to shorten end-of-DL tail

Issue : on a 14 GB download with 8 segments, when 7 finish there's only
1 connection left handling its assigned 1.75 GB → apparent throughput
collapses to 1/8th of the peak for the final stretch (~5 min visible
slowdown at the end).

Quick fix : double the default segment count.
- 8 segments  : last has 1.75 GB to finish alone
- 16 segments : last has 875 MB → tail ~halved

Tuning surfaced in Settings → Avancés → Serveur as
« Connexions parallèles pour les téléchargements (1-32, défaut 16) ».
Power users on faster servers can push to 24-32. OVH mutualisé tolerates
up to 16-24 ; above that, soft rate-limiting kicks in.

Aligned :
- LocalConfig default : 8 → 16
- DownloadManager clamp : Math.Clamp(_, 1, 16) → 1, 32
- HttpClient handler MaxConnectionsPerServer : 16 → 32 (matches new ceiling)

Versions bumped to 0.19.0.

Existing config.json files will keep their previous value (8) untouched ;
delete config.json to pick up the new default, or just bump it in
Settings → Avancés.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/PSLauncher.App/App.xaml.cs

@@ -112,16 +112,16 @@ public partial class App : Application
                 services.AddSingleton(sp =>
                 {
                     // Handler tuné pour les gros téléchargements parallèles :
-                    // - MaxConnectionsPerServer=16 pour autoriser le multi-segment (8 par défaut).
-                    // - AutomaticDecompression sur l'API JSON uniquement (None ici car les builds
-                    //   sont des ZIPs déjà compressés ; éviter la CPU+RAM gaspillée par un éventuel
-                    //   wrapping gzip côté serveur).
+                    // - MaxConnectionsPerServer=32 pour aligner avec le clamp DownloadManager (8-32).
+                    //   Default WPF = 8 → trop bas pour notre multi-segment.
+                    // - AutomaticDecompression=None : les builds sont des ZIPs déjà compressés ;
+                    //   éviter la CPU+RAM gaspillée par un éventuel wrapping gzip côté serveur.
                     // - PooledConnectionLifetime court pour éviter qu'OVH ferme nos sockets sous nous.
                     var handler = new SocketsHttpHandler
                     {
                         PooledConnectionLifetime = TimeSpan.FromMinutes(5),
                         PooledConnectionIdleTimeout = TimeSpan.FromSeconds(60),
-                        MaxConnectionsPerServer = 16,
+                        MaxConnectionsPerServer = 32,
                         EnableMultipleHttp2Connections = true,
                         AutomaticDecompression = System.Net.DecompressionMethods.None,
                     };

src/PSLauncher.App/PSLauncher.App.csproj

@@ -15,9 +15,9 @@
     <Product>PROSERVE Launcher</Product>
     <Copyright>© 2026 ASTERION VR — All rights reserved</Copyright>
     <RootNamespace>PSLauncher.App</RootNamespace>
-    <Version>0.18.0</Version>
-    <AssemblyVersion>0.18.0.0</AssemblyVersion>
-    <FileVersion>0.18.0.0</FileVersion>
+    <Version>0.19.0</Version>
+    <AssemblyVersion>0.19.0.0</AssemblyVersion>
+    <FileVersion>0.19.0.0</FileVersion>
 
     <!-- Single-file self-contained publish profile (used by `dotnet publish`) -->
     <PublishSingleFile>true</PublishSingleFile>

src/PSLauncher.App/ViewModels/SettingsViewModel.cs

@@ -49,6 +49,7 @@ public sealed partial class SettingsViewModel : ObservableObject
     [ObservableProperty] private string _language;
     [ObservableProperty] private string _reportUrl;
     [ObservableProperty] private string _documentationUrl;
+    [ObservableProperty] private int _parallelSegments;
 
     // ----- DB Migration settings -----
     [ObservableProperty] private string _dbHost;
@@ -173,6 +174,7 @@ public sealed partial class SettingsViewModel : ObservableObject
         _language = string.IsNullOrWhiteSpace(config.Language) ? "auto" : config.Language;
         _reportUrl = config.ReportUrl;
         _documentationUrl = config.DocumentationUrl;
+        _parallelSegments = config.ParallelDownloadSegments;
 
         _dbHost = config.Database.Host;
         _dbPort = config.Database.Port;
@@ -303,6 +305,7 @@ public sealed partial class SettingsViewModel : ObservableObject
         _config.Language = Language ?? "auto";
         _config.ReportUrl = ReportUrl?.Trim() ?? "";
         _config.DocumentationUrl = DocumentationUrl?.Trim() ?? "";
+        _config.ParallelDownloadSegments = Math.Clamp(ParallelSegments, 1, 32);
 
         // DB settings
         _config.Database.Host = DbHost.Trim();

src/PSLauncher.App/Views/SettingsDialog.xaml

@@ -230,6 +230,19 @@
                                  Background="#1A1A20" Foreground="{StaticResource Brush.Text.Primary}"
                                  BorderBrush="{StaticResource Brush.Border}" BorderThickness="1" Padding="8"
                                  FontFamily="Consolas" />
+
+                        <!-- Connexions parallèles : tuning de la queue de fin de DL -->
+                        <TextBlock Text="{x:Static loc:Strings.SettingsParallelSegments}"
+                                   Foreground="{StaticResource Brush.Text.Secondary}"
+                                   FontSize="12" Margin="0,16,0,4" />
+                        <TextBox Text="{Binding ParallelSegments, UpdateSourceTrigger=PropertyChanged}"
+                                 Background="#1A1A20" Foreground="{StaticResource Brush.Text.Primary}"
+                                 BorderBrush="{StaticResource Brush.Border}" BorderThickness="1" Padding="8"
+                                 Width="80" HorizontalAlignment="Left" />
+                        <TextBlock Text="{x:Static loc:Strings.SettingsParallelSegmentsHint}"
+                                   Foreground="{StaticResource Brush.Text.Secondary}"
+                                   FontSize="11" FontStyle="Italic" Margin="0,4,0,0"
+                                   TextWrapping="Wrap" />
                     </StackPanel>
                 </Border>