v0.6 + v1.0: HMAC download URLs, launcher self-update, Inno Setup installer

Three deliverables shipped together so the next deployment cycle has a
clean distribution story.

(1) Auto-update of the launcher itself
---------------------------------------
- Models: RemoteManifest gains an optional `launcher` section
  (LauncherInfo: version, minRequired, download {url,size,sha256},
   releaseNotesUrl). Server-side, sign-manifest.php passes it through
  unchanged; admins edit versions.json with the new launcher entry +
  upload PSLauncher-X.Y.Z.exe to /builds/launcher/.
- Core: ILauncherSelfUpdater compares assembly version against
  manifest.launcher.version using the existing SemVer parser, and
  reuses DownloadManager (Range/resume/sha256 already proven on the
  game ZIPs) to download the new exe into
  %LocalAppData%/PSLauncher/selfupdate/.
- New project PSLauncher.Updater (~34 MB self-contained console exe):
  spawned by the main app with --target / --source / --pid / --launch.
  Waits for the main process to exit (or for the file lock to release),
  backs up the current exe to .bak, copies the new file in place, and
  restarts. .bak survives the swap so the user can roll back manually.
- App.csproj now declares Version=0.5.0 — currently shipped baseline.
  PSLauncher.App.csproj sets a fixed AssemblyVersion so reflection-based
  comparison works deterministically.
- MainViewModel.PromptLauncherUpdate: dialog after CheckForUpdates if
  the manifest advertises a newer launcher. Download with progress in
  the existing footer, then Application.Shutdown() so the Updater can
  do its job.

(2) Inno Setup installer
------------------------
installer/PSLauncher.iss + build-installer.ps1 produce a single
PSLauncher-Setup-X.Y.Z.exe (~80 MB) that installs into
Program Files\ASTERION VR\PSLauncher\, drops both PSLauncher.exe and
PSLauncher.Updater.exe side by side (the updater MUST live next to
the target), creates Start Menu + optional Desktop shortcuts, and
registers a clean uninstall entry. The user's %LocalAppData%
(license, logs, cache) is intentionally untouched on uninstall — same
license survives a reinstall.

build-installer.ps1 chains dotnet publish for both projects and ISCC
in one command. README explains the bump-version workflow.

(3) HMAC-signed download URLs
-----------------------------
- New PHP route GET /api/download-url/{version} (Authorization: Bearer
  <licenseKey> or ?key=...). Validates the license, checks
  download_entitlement_until >= minLicenseDate of the version, and
  returns a HMAC-signed URL (path|exp|licId, hash_hmac SHA-256, valid
  1 h) + sha256 + sizeBytes for verification.
- /builds/.htaccess routes every *.zip request to gate.php. gate.php
  validates exp, lic, sig (constant-time hash_equals), then streams
  the file with Range: support so the launcher's resume keeps working.
  Audit log gets a download_url_issued entry per request.
- Client-side wired transparently: LicenseService gains
  GetSignedDownloadUrlAsync(version) that GETs the endpoint with the
  decrypted license key from DPAPI. MainViewModel calls it before
  every download; if the endpoint returns 404/401/network-error, the
  client falls back to the manifest's plain download.url (graceful
  degradation for setups that haven't deployed gate.php yet).

Note on PHP streaming for 14 GB ZIPs: gate.php uses set_time_limit(0)
+ ignore_user_abort(true) + 1 MiB chunked fread with periodic flush.
Works on OVH mutualisé but holds a PHP-FPM slot for the duration. If
parallel downloads scale past a few clients, switch to
mod_xsendfile or migrate /builds/ to Cloudflare R2 with native
S3-presigned URLs and remove the gate entirely.

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

src/PSLauncher.Core/Updates/ILauncherSelfUpdater.cs

@@ -0,0 +1,20 @@
+using PSLauncher.Models;
+
+namespace PSLauncher.Core.Updates;
+
+public interface ILauncherSelfUpdater
+{
+    /// <summary>Compare la version courante avec celle annoncée dans le manifest.</summary>
+    bool IsNewerThanCurrent(LauncherInfo launcher);
+
+    string GetCurrentVersion();
+
+    /// <summary>
+    /// Télécharge le nouveau binaire dans un dossier de staging et déclenche l'updater.
+    /// L'application courante doit s'arrêter rapidement après le retour de cette méthode.
+    /// </summary>
+    Task<bool> DownloadAndApplyAsync(
+        LauncherInfo launcher,
+        IProgress<DownloadProgress>? progress,
+        CancellationToken ct);
+}

src/PSLauncher.Core/Updates/LauncherSelfUpdater.cs

@@ -0,0 +1,106 @@
+using System.Diagnostics;
+using System.Reflection;
+using Microsoft.Extensions.Logging;
+using PSLauncher.Core.Configuration;
+using PSLauncher.Core.Downloads;
+using PSLauncher.Core.Installations;
+using PSLauncher.Models;
+using SysProcess = System.Diagnostics.Process;
+
+namespace PSLauncher.Core.Updates;
+
+public sealed class LauncherSelfUpdater : ILauncherSelfUpdater
+{
+    private readonly IDownloadManager _downloadManager;
+    private readonly IConfigStore _configStore;
+    private readonly ILogger<LauncherSelfUpdater> _logger;
+
+    public LauncherSelfUpdater(
+        IDownloadManager downloadManager,
+        IConfigStore configStore,
+        ILogger<LauncherSelfUpdater> logger)
+    {
+        _downloadManager = downloadManager;
+        _configStore = configStore;
+        _logger = logger;
+    }
+
+    public string GetCurrentVersion()
+    {
+        var asm = Assembly.GetEntryAssembly() ?? Assembly.GetExecutingAssembly();
+        var v = asm.GetName().Version;
+        return v is null ? "0.0.0" : $"{v.Major}.{v.Minor}.{v.Build}";
+    }
+
+    public bool IsNewerThanCurrent(LauncherInfo launcher)
+    {
+        var current = SemVer.Parse(GetCurrentVersion());
+        var remote  = SemVer.Parse(launcher.Version);
+        return remote.CompareTo(current) > 0;
+    }
+
+    public async Task<bool> DownloadAndApplyAsync(
+        LauncherInfo launcher,
+        IProgress<DownloadProgress>? progress,
+        CancellationToken ct)
+    {
+        // 1. Localise le PSLauncher.exe en cours d'exécution
+        var processModule = SysProcess.GetCurrentProcess().MainModule
+                            ?? throw new InvalidOperationException("Cannot locate current process module");
+        var targetExe = processModule.FileName!;
+        var installDir = Path.GetDirectoryName(targetExe)!;
+        _logger.LogInformation("Self-update target: {Path}", targetExe);
+
+        // 2. Télécharge le nouveau exe dans le cache
+        var stagingDir = Path.Combine(_configStore.ConfigDirectory, "selfupdate");
+        Directory.CreateDirectory(stagingDir);
+
+        var downloadJob = new DownloadJob(
+            $"launcher-{launcher.Version}",
+            new Uri(launcher.Download.Url),
+            launcher.Download.SizeBytes,
+            launcher.Download.Sha256);
+
+        var downloadedPath = await _downloadManager.DownloadAsync(downloadJob, progress, ct).ConfigureAwait(false);
+        _logger.LogInformation("New launcher downloaded to {Path}", downloadedPath);
+
+        // 3. Localise PSLauncher.Updater.exe (à côté du target)
+        var updaterPath = Path.Combine(installDir, "PSLauncher.Updater.exe");
+        if (!File.Exists(updaterPath))
+        {
+            // Fallback : tente de copier l'updater depuis le dossier d'install vers un staging
+            // si jamais il a été supprimé. Pour la v1, on demande à l'utilisateur de réinstaller.
+            throw new FileNotFoundException(
+                "PSLauncher.Updater.exe est manquant à côté de PSLauncher.exe. " +
+                "Réinstalle le launcher depuis l'installeur officiel.",
+                updaterPath);
+        }
+
+        // 4. Copie le .new dans le staging dir si downloaded est ailleurs
+        var newPath = Path.Combine(stagingDir, $"PSLauncher-{launcher.Version}.exe");
+        if (!string.Equals(downloadedPath, newPath, StringComparison.OrdinalIgnoreCase))
+        {
+            if (File.Exists(newPath)) File.Delete(newPath);
+            File.Move(downloadedPath, newPath);
+        }
+
+        // 5. Lance l'updater détaché
+        var pid = Environment.ProcessId;
+        var psi = new ProcessStartInfo
+        {
+            FileName = updaterPath,
+            UseShellExecute = false,
+            CreateNoWindow = true,
+        };
+        psi.ArgumentList.Add($"--target={targetExe}");
+        psi.ArgumentList.Add($"--source={newPath}");
+        psi.ArgumentList.Add($"--pid={pid}");
+        psi.ArgumentList.Add("--launch");
+
+        _logger.LogInformation("Spawning updater {Updater} (target={Target}, source={Source}, pid={Pid})",
+            updaterPath, targetExe, newPath, pid);
+        SysProcess.Start(psi);
+
+        return true; // l'appelant doit Application.Current.Shutdown() après
+    }
+}