branding: ASTERION VR favicon + copyright everywhere

Icon
----
src/favicon64.jpg converted to favicon.ico (single-resolution 64x64)
via PowerShell + System.Drawing.Icon.FromHandle. The .ico is now an
EmbeddedResource of PSLauncher.App and referenced as:
- <ApplicationIcon> on PSLauncher.App.csproj → .exe icon in
  Explorer / taskbar / Alt-Tab
- Window.Icon on every WPF window: MainWindow, SettingsDialog,
  OnboardingDialog, LicenseDetailsDialog, UpdateAvailableDialog,
  ReleaseNotesViewerDialog, LauncherUpdateDialog
- <ApplicationIcon> on PSLauncher.Updater.csproj → updater also
  carries the brand icon
- SetupIconFile in installer/PSLauncher.iss → the Inno Setup .exe
  installer shows the icon too

Copyright
---------
- <Company>, <Product>, <Copyright> assembly attributes set in
  both csprojs → properties dialog on the .exe shows "© ASTERION VR".
- MainWindow body has a discreet floating "© ASTERION VR" text in the
  bottom-right, mirroring the "Vérifier les MAJ" button on the left.
  Opacity 0.7 + secondary color so it doesn't compete with the cards.
- SettingsDialog "Logs & Application" section gains a
  "© ASTERION VR — Tous droits réservés" line under the version.

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

src/PSLauncher.App/PSLauncher.App.csproj

@@ -9,8 +9,11 @@
     <Nullable>enable</Nullable>
     <LangVersion>latest</LangVersion>
     <ImplicitUsings>enable</ImplicitUsings>
-    <ApplicationIcon></ApplicationIcon>
+    <ApplicationIcon>Resources\favicon.ico</ApplicationIcon>
     <AssemblyName>PSLauncher</AssemblyName>
+    <Company>ASTERION VR</Company>
+    <Product>PROSERVE Launcher</Product>
+    <Copyright>© ASTERION VR</Copyright>
     <RootNamespace>PSLauncher.App</RootNamespace>
     <Version>0.7.0</Version>
     <AssemblyVersion>0.7.0.0</AssemblyVersion>
@@ -47,6 +50,7 @@
   <ItemGroup>
     <Resource Include="Resources\Background.png" />
     <Resource Include="Resources\pirulen.otf" />
+    <Resource Include="Resources\favicon.ico" />
   </ItemGroup>
 
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