backoffice: drop the redundant launcher Sync button

Reverting the previous addition. The blue "🔁 Recalculer hash + signer"
button on the launcher card called the same 'sync' action as the
global one in the manifest table — same code path, same effect. Two
identical buttons created confusion. The workflow text now points
operators to the existing global Sync button below, and only the
launcher-specific actions (Définir / Retirer) live on the launcher
card.

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

server/admin/versions.php

@@ -295,15 +295,9 @@ 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 <strong>🔁 Recalculer hash + signer</strong> ci-dessous (équivalent au Sync global mais lancé depuis cette card).</li>
+        <li>Clique <strong>🔁 Sync (sign-manifest)</strong> dans le tableau du manifest ci-dessous — il hashera la section launcher en plus des versions Proserve.</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">