Initial scaffolding: PS_Launcher v0.2

Client (C# / .NET 8 / WPF, MVVM via CommunityToolkit.Mvvm):
- PSLauncher.App: WPF UI dark theme (Epic-style sidebar + hero + big play button)
  with UpdateAvailableDialog rendering Markdown release notes via Markdig.Wpf.
- PSLauncher.Core: services for installation registry (scans Proserve v{X.Y.Z}/),
  process launcher, manifest fetch, SHA-256 integrity, HTTP download with
  progress, ZIP install via .tmp + atomic rename, update orchestrator.
- PSLauncher.Models: RemoteManifest, InstalledVersion, LocalConfig DTOs.

Server (PHP 8 for OVH mutualisé, deployed under www/PS_Launcher/):
- Front controller + routes /manifest and /releasenotes/{version}.
- Static signed-manifest workflow with tools/sign-manifest.php CLI to
  recompute SHA-256 and sizeBytes after each ZIP upload.
- .htaccess: HTTPS redirect, rewrite, security headers.
- config.example.php template; real config.php is gitignored.

Cohabiting versions: each release lives in its own Proserve v{version}/ folder
under installRoot. Old versions are never deleted automatically.

Roadmap: v0.3 = HTTP Range resume + Polly retry + state.json,
v0.4 = MySQL license + Ed25519 signatures + DPAPI, v0.5 = settings/UX polish.

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

src/PSLauncher.App/ViewModels/InstalledVersionViewModel.cs

@@ -0,0 +1,27 @@
+using PSLauncher.Models;
+
+namespace PSLauncher.App.ViewModels;
+
+public sealed class InstalledVersionViewModel
+{
+    public InstalledVersion Model { get; }
+
+    public InstalledVersionViewModel(InstalledVersion model) => Model = model;
+
+    public string Display => $"v{Model.Version}";
+
+    public string Subtitle =>
+        $"{FormatSize(Model.SizeBytes)} • Installée le {Model.InstalledAt.ToLocalTime():dd/MM/yyyy}";
+
+    private static string FormatSize(long bytes)
+    {
+        if (bytes <= 0) return "—";
+        string[] units = { "o", "Ko", "Mo", "Go", "To" };
+        double v = bytes;
+        int u = 0;
+        while (v >= 1024 && u < units.Length - 1) { v /= 1024; u++; }
+        return $"{v:0.#} {units[u]}";
+    }
+
+    public override string ToString() => Display;
+}