backoffice: add a blue "Sync" button on the launcher card itself

Operator setting up auto-update was forced to scroll down to the
"Manifest actuel" card and find the global Sync button after each step
of the launcher workflow. Add a dedicated "🔁 Recalculer hash + signer"
primary-blue button right inside the launcher card. It posts the same
action='sync' so behavior is identical — it's just discoverable from
where the operator is looking.

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

server/admin/versions.php

@@ -295,9 +295,15 @@ Layout::header('Versions', 'versions');
     <ol class="muted">
         <li>Définis la version ci-dessus (ex : <code>0.6.0</code>).</li>
         <li>Upload <code>PSLauncher-X.Y.Z.exe</code> via SFTP dans <code>www/PS_Launcher/builds/launcher/</code>.</li>
-        <li>Clique le bouton <strong>🔁 Sync (sign-manifest)</strong> du tableau du dessous — il hashera le launcher en plus des versions Proserve.</li>
+        <li>Clique <strong>🔁 Recalculer hash + signer</strong> ci-dessous (équivalent au Sync global mais lancé depuis cette card).</li>
     </ol>
 
+    <form method="post" style="margin-top: 12px;">
+        <?= Layout::csrfField() ?>
+        <input type="hidden" name="action" value="sync">
+        <button class="btn btn-primary" type="submit">🔁 Recalculer hash + signer le manifest</button>
+    </form>
+
     <?php if (!empty($launcherFiles)): ?>
     <h3 style="margin-top: 18px; font-size: 13px; color: var(--text-secondary); text-transform: uppercase;">Exes présents dans builds/launcher/</h3>
     <ul class="muted">