VisualLimsApiClientMock: fake data for all LIMS endpoints; getInstance() branches on SIMULATE_EXPORT_LIMS

get_clienti.php, get_fixed_field_data.php: simulate mode support
CustomField dropdown values mock added (get_customfield_values.php)

exportUnsavedModal: prompt save before export, MutationObserver waits for save, then proceeds to confirm
Removed old jQuery .export-lims-btn handler that bypassed confirm modal
Fix false "Unsaved changes" on page load: data-restoring guard in all programmatic trigger/dispatchEvent calls (populateSelect, populateClientDropdowns, populateDropdowns)

Fix ConsegnaRichiesta not shown on refresh: add to PHP $fixedAliasMap
Add step5_2_photos, step9_1_importa

public/userarea/get_clienti.php

@@ -9,7 +9,24 @@ ini_set('display_errors', '0');
 error_reporting(E_ALL);
 
 try {
-    $api = VisualLimsApiClient::getInstance();
+    $api = VisualLimsApiClient::getInstance(); // also loads dotenv
+
+    // In simulate mode: return fake clients built from idclient values already in datadb.
+    // This ensures client dropdowns auto-select the correct row idclient, which in turn
+    // triggers the ClienteResponsabile select to populate via the mock.
+    if (($_ENV['SIMULATE_EXPORT_LIMS'] ?? '') === 'true') {
+        require_once __DIR__ . '/class/db-functions.php';
+        $pdo = DBHandlerSelect::getInstance()->getConnection();
+        $stmt = $pdo->query("SELECT DISTINCT idclient FROM datadb WHERE idclient IS NOT NULL AND idclient > 0 ORDER BY idclient ASC");
+        $ids = $stmt->fetchAll(PDO::FETCH_COLUMN);
+        $fakeClients = array_map(fn($id) => [
+            'IdCliente'    => (int) $id,
+            'Nominativo'   => "Cliente Simulato {$id}",
+            'CodiceCliente' => "SIM_{$id}",
+        ], $ids);
+        echo json_encode(['value' => $fakeClients]);
+        exit;
+    }
 
     // Parametri OData
     $params = [