UI overhaul: minimal top bar, license-first settings, footer-pinned check

Top bar (3-column layout)
-------------------------
- Col 1: PROSERVE Launcher wordmark.
- Col 2: license badge centered, the badge IS the click target now (a
  Border with an InputBindings MouseBinding LeftClick to OpenLicense).
  No more separate "🔑 Activer / changer" button cluttering the right.
- Col 3: ⚙ Paramètres + window chrome (min/max/close).
- "📁 Dossier" button removed from the top bar — install root is still
  reachable from Settings.

Footer (always visible)
-----------------------
- Row 1: "🔄 Vérifier les MAJ" pinned bottom-left, always shown. The
  optional "Annuler" button stays bottom-right while a download runs.
- Row 2: status text + progress bar, only shown when busy or after a
  status message — the previous "footer entirely hidden when idle"
  hid the check button too.

License flow split in two
-------------------------
Click on the license badge:
- License is active (valid / expired / revoked) → LicenseDetailsDialog
  opens. Header pill in matching status color (green/amber/red), shows
  owner, validity, issued date, machine ID with copy-to-clipboard. Two
  buttons: "🗑 Désactiver la license" (with confirmation) and Close.
- No license OR after deactivation → falls through to the existing
  OnboardingDialog for re-keying.

Settings rework
---------------
LICENSE section is now first in SettingsDialog with the same
green/amber/red colored chrome as the top bar — at a glance the user
sees the same status everywhere. Machine ID copy moved into this card.

Sign-manifest no longer needs exec()
------------------------------------
The "🔁 Sync" button in admin/versions.php previously shelled out to
`php tools/sign-manifest.php` via exec(). OVH mutualisé often disables
exec(), causing silent no-ops and the symptom the user just hit: the
ZIP changed (new size 469,657,770 vs manifest's stale 469,831,428) and
the launcher rejected it as size mismatch.

Refactor:
- New PSLauncher\Tools\SignManifest class with ->run() that does the
  hashing, latest-bump and Ed25519 signing in-process.
- tools/sign-manifest.php is now a 6-line wrapper for the class.
- admin/versions.php's 'sync' action calls the class directly via
  require_once + new — works on any host, no exec dependency.

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

src/PSLauncher.App/ViewModels/MainViewModel.cs

@@ -315,12 +315,41 @@ public sealed partial class MainViewModel : ObservableObject
         }
     }
 
+    /// <summary>
+    /// Clic sur le badge license dans la top bar.
+    /// - License active (valid/expired/revoked) → ouvre LicenseDetailsDialog (détails + désactiver)
+    /// - Sinon → ouvre OnboardingDialog (saisie de clé)
+    /// Si l'utilisateur désactive depuis les détails, on enchaîne sur l'onboarding pour
+    /// faciliter le re-keying éventuel — sinon on revient simplement à l'état "Aucune license".
+    /// </summary>
     [RelayCommand]
-    private async Task ActivateLicenseAsync()
+    private async Task OpenLicenseAsync()
     {
-        var dialog = new Views.OnboardingDialog(_licenseService) { Owner = Application.Current.MainWindow };
-        dialog.ShowDialog();
-        if (dialog.LicenseActivated)
+        var current = _licenseService.GetCached();
+
+        if (current is not null)
+        {
+            var details = new Views.LicenseDetailsDialog(_licenseService, current)
+            {
+                Owner = Application.Current.MainWindow
+            };
+            details.ShowDialog();
+            if (!details.DeactivateRequested)
+            {
+                // Pas de changement
+                await Task.CompletedTask;
+                return;
+            }
+            // Désactivation : on a déjà vidé le cache, on rafraîchit la UI puis on reboucle
+            _license = null;
+            NotifyLicenseChanged();
+            RebuildList();
+        }
+
+        // Aucune license → propose l'onboarding
+        var onboard = new Views.OnboardingDialog(_licenseService) { Owner = Application.Current.MainWindow };
+        onboard.ShowDialog();
+        if (onboard.LicenseActivated)
         {
             _license = _licenseService.GetCached();
             NotifyLicenseChanged();