i18n: full pass + culture-aware dates/sizes + Software Update License wording

- Strings.cs : ~80 new keys covering status messages, progress detail
  (DL/extraction/verify), license summary, license details dialog, onboarding
  statuses, settings field labels, restart/cancel/quit confirmations, toasts,
  resume choice, copyright. Strings.FormatSize and Strings.FormatDate /
  FormatLongDate switch units (o/Ko vs B/KB) and pattern (dd/MM/yyyy vs M/d/yyyy
  vs 2026年) by active language.
- License terminology renamed across UI: "License" → "License de mise à jour"
  / "Software Update License" to clarify it gates UPDATES, not Proserve itself.
  Expired/revoked dialogs now spell out "you can still download versions
  released before this date and launch any installed version".
- "🔒 License insuffisante" → "🔒 License de mise à jour requise pour cette
  version" / "Valid update license needed for this version" so users understand
  it's a per-version eligibility check, not a global block.
- All hardcoded FR strings in views (SettingsDialog labels, LicenseDetails
  fields, Onboarding statuses, dialog titles, copyright, window chrome
  tooltips, "Sortie le", etc.) replaced with x:Static loc bindings.
- All FormatSize duplicates (5 places) and date format strings (8 places)
  delegate to Strings helpers — single source of truth for localization.
- Settings dialog: License section moved to the top before Language. It's
  the most important info and conditions what the user can download.

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

src/PSLauncher.App/Views/ReleaseNotesViewerDialog.xaml

@@ -1,7 +1,8 @@
 <Window x:Class="PSLauncher.App.Views.ReleaseNotesViewerDialog"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-        Title="Notes de version"
+        xmlns:loc="clr-namespace:PSLauncher.Core.Localization;assembly=PSLauncher.Core"
+        Title="{x:Static loc:Strings.MsgBoxReleaseNotes}"
         Icon="pack://application:,,,/Resources/favicon.ico"
         Width="640" Height="540"
         MinWidth="480" MinHeight="400"
@@ -33,7 +34,7 @@
 
         <Button Grid.Row="2"
                 Style="{StaticResource SecondaryButton}"
-                Content="Fermer"
+                Content="{x:Static loc:Strings.ActionClose}"
                 IsCancel="True"
                 IsDefault="True"
                 HorizontalAlignment="Right"