Add saved searches with CRUD API and UI sidebar

Add extension field to search results and display it
Add active filter badges and save button to search header

frontend/index.html

@@ -320,6 +320,11 @@
             <i data-lucide="clock" style="width:13px;height:13px"></i>
             <span>Récent</span>
           </button>
+          <button class="sidebar-tab" id="sidebar-tab-saved" role="tab"
+                  aria-selected="false" aria-controls="sidebar-panel-saved" data-tab="saved">
+            <i data-lucide="bookmark" style="width:13px;height:13px"></i>
+            <span>Sauvegardes</span>
+          </button>
         </div>
 
         <!-- Vaults panel -->
@@ -356,6 +361,15 @@
           </div>
         </div>
 
+        <!-- Saved Searches panel -->
+        <div class="sidebar-tab-panel" id="sidebar-panel-saved" role="tabpanel" aria-labelledby="sidebar-tab-saved">
+          <div id="saved-searches-list" class="recent-list"></div>
+          <div id="saved-searches-empty" class="recent-empty">
+            <i data-lucide="bookmark" style="width:32px;height:32px"></i>
+            <span>Aucune recherche sauvegardée</span>
+          </div>
+        </div>
+
       </aside>
 
       <!-- Sidebar resize handle -->