Index page: remove Mots-clés button, move export to bulk selection, fix ZipArchive error, move DB export to paramètres, sticky thead

- Remove 'Mots-clés' button from toolbar (redundant with admin sidebar tags)
- Replace export dialog with 'Exporter CSV' + 'Exporter fichiers' buttons in bulk selection bar
- Export dispatcher now accepts ?ids=1,2,3 for per-selection export
- All ExportController/Database methods accept optional thesisIds array
- Graceful error message when ZipArchive extension is missing on server
- Move DB export (SQLite download) to paramètres → Maintenance section
- Sticky table column headers (position: sticky, top: 0, z-index: 5) for index page table

app/templates/admin/index.php

@@ -1,8 +1,11 @@
 <script>
 function toggleAll(src){document.querySelectorAll('input[name="selected_theses[]"]').forEach(cb=>cb.checked=src.checked);updateBulk();}
 function updateBulk(){const n=document.querySelectorAll('input[name="selected_theses[]"]:checked').length;const b=document.getElementById('bulk-actions');document.getElementById('selected-count').textContent=n;b.style.display=n>0?'flex':'none';}
-function confirmBulk(act){const n=document.querySelectorAll('input[name="selected_theses[]"]:checked').length;if(!n){document.getElementById('no-selection-dialog').showModal();return;}document.getElementById('bulk-action-input').value=act;if(act==='delete'){document.getElementById('bulk-delete-count').textContent=n;document.getElementById('bulk-delete-dialog').showModal();}else{document.getElementById('bulk-confirm-word').textContent=act==='publish'?'Publier':'Dépublier';document.getElementById('bulk-confirm-count').textContent=n;document.getElementById('bulk-confirm-dialog').showModal();}}
-function execBulk(){const a=document.getElementById('bulk-action-input').value;const f=document.getElementById('bulk-form');f.action = a==='delete' ? 'actions/delete.php' : 'actions/publish.php';const c=document.getElementById('bulk-checkboxes');c.innerHTML='';document.querySelectorAll('input[name="selected_theses[]"]:checked').forEach(cb=>{const inp=document.createElement('input');inp.type='hidden';inp.name='selected_theses[]';inp.value=cb.value;c.appendChild(inp);});f.submit();}
+function getSelectedIds(){return Array.from(document.querySelectorAll('input[name="selected_theses[]"]:checked')).map(cb=>cb.value);}
+function confirmBulk(act){const ids=getSelectedIds();if(!ids.length){document.getElementById('no-selection-dialog').showModal();return;}const n=ids.length;document.getElementById('bulk-action-input').value=act;if(act==='delete'){document.getElementById('bulk-delete-count').textContent=n;document.getElementById('bulk-delete-dialog').showModal();}else{document.getElementById('bulk-confirm-word').textContent=act=='publish'?'Publier':'Dépublier';document.getElementById('bulk-confirm-count').textContent=n;document.getElementById('bulk-confirm-dialog').showModal();}}
+function execBulk(){const a=document.getElementById('bulk-action-input').value;const f=document.getElementById('bulk-form');f.action = a=='delete' ? 'actions/delete.php' : 'actions/publish.php';const c=document.getElementById('bulk-checkboxes');c.innerHTML='';getSelectedIds().forEach(id=>{const inp=document.createElement('input');inp.type='hidden';inp.name='selected_theses[]';inp.value=id;c.appendChild(inp);});f.submit();}
+function confirmExport(){const ids=getSelectedIds();if(!ids.length){document.getElementById('no-selection-dialog').showModal();return;}window.location.href='/admin/actions/export.php?csv=1&ids='+ids.join(',');}
+function confirmExportFiles(){const ids=getSelectedIds();if(!ids.length){document.getElementById('no-selection-dialog').showModal();return;}window.location.href='/admin/actions/export.php?files=1&ids='+ids.join(',');}
 function confirmDelete(id,title){document.getElementById('delete-thesis-title').textContent=title;document.getElementById('delete-thesis-dialog').showModal();document.getElementById('delete-dialog-confirm').onclick=function(){document.getElementById('delete-form-'+id).submit();};}
 document.addEventListener('DOMContentLoaded',()=>{document.querySelectorAll('input[name="selected_theses[]"]').forEach(cb=>cb.addEventListener('change',updateBulk));});
 document.addEventListener('htmx:afterSwap',()=>{document.querySelectorAll('input[name="selected_theses[]"]').forEach(cb=>cb.addEventListener('change',updateBulk));updateBulk();});
@@ -31,7 +34,6 @@ document.addEventListener('htmx:afterSwap',()=>{document.querySelectorAll('input
             </div>
             <div class="admin-btn-group">
                 <a href="/admin/add.php" class="btn btn--primary btn--sm">+ Ajouter un TFE</a>
-                <a href="/admin/tags.php" class="btn btn--primary btn--sm">Mots-clés</a>
                 <?php if ($trashCount > 0): ?>
                 <a href="/admin/index.php?tab=trash" class="btn btn--sm <?= $tab === 'trash' ? 'btn--primary' : 'btn--secondary' ?>">
                     Corbeille (<?= $trashCount ?>)
@@ -47,10 +49,6 @@ document.addEventListener('htmx:afterSwap',()=>{document.querySelectorAll('input
                         onclick="document.getElementById('import-dialog').showModal()">
                     Importer
                 </button>
-                <button type="button" class="btn btn--primary btn--sm" id="export-dialog-btn"
-                        onclick="document.getElementById('export-dialog').showModal()">
-                    Exporter
-                </button>
             </div>
         </div>
 
@@ -244,43 +242,6 @@ document.addEventListener('htmx:afterSwap',()=>{document.querySelectorAll('input
     <?php endif; ?>
 </dialog>
 
-<!-- ══════════════════════════════════════════════════════════════
-     EXPORT DIALOG
-══════════════════════════════════════════════════════════════ -->
-<dialog id="export-dialog" class="admin-dialog admin-dialog--sm" aria-labelledby="export-dialog-title">
-    <div class="admin-dialog__header">
-        <h2 id="export-dialog-title">Exporter</h2>
-        <button type="button" class="admin-dialog__close" aria-label="Fermer"
-                onclick="document.getElementById('export-dialog').close()">&#x2715;</button>
-    </div>
-
-    <form method="get" action="/admin/actions/export.php" class="admin-form">
-        <div class="admin-form-group">
-            <label class="admin-checkbox-label">
-                <input type="checkbox" name="csv" value="1" checked>
-                CSV (tableau des métadonnées)
-            </label>
-        </div>
-        <div class="admin-form-group">
-            <label class="admin-checkbox-label">
-                <input type="checkbox" name="files" value="1" checked>
-                Fichiers (archive ZIP)
-            </label>
-        </div>
-        <div class="admin-form-group">
-            <label class="admin-checkbox-label">
-                <input type="checkbox" name="db" value="1">
-                Base de données (SQLite)
-            </label>
-        </div>
-        <div class="admin-form-footer">
-            <button type="submit" class="btn btn--primary">Exporter</button>
-            <button type="button" class="btn btn--secondary"
-                    onclick="document.getElementById('export-dialog').close()">Annuler</button>
-        </div>
-    </form>
-</dialog>
-
 <!-- ══════════════════════════════════════════════════════════════
      TMP CLEANUP DIALOG
 ══════════════════════════════════════════════════════════════ -->