v1.8.1: Alignement upload offline sur le flow online (UX + self-heal)

L'upload offline avait deux defauts vs l'update online:
- pas de self-heal des services (pas de Step 3c equivalent)
- ancienne UX synchrone (spinner sans feedback pendant 60-90s)

Maintenant:
- update_firmware_from_file.sh: nouveau Step 4c qui appelle
  setup_services.sh (alignement avec online)
- launcher.php upload_firmware: lance le script en background et
  reutilise le mecanisme log/done de l'update online
- admin.html uploadFirmware: apres l'upload du ZIP, bascule sur
  le meme systeme de polling/progress que l'online (avec mapping
  d'etapes specifique au script offline)
- Detection de fin par substring 'completed successfully!' (matche
  les 2 markers finaux differents)

Fix au passage: le bouton 'Upload & Install' restait bloque sur
'Installing...' apres succes.

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

html/launcher.php

@@ -578,19 +578,31 @@ if ($type == "upload_firmware") {
 
     $new_version = trim(file_get_contents("$source_dir/VERSION"));
 
-    // Execute update script
-    $command = "sudo /var/www/nebuleair_pro_4g/update_firmware_from_file.sh '$source_dir' 2>&1";
-    $output = shell_exec($command);
+    // Launch update script in background, reusing the same log/done file mechanism
+    // as the online update. The frontend can then poll update_firmware_progress
+    // to get a live view and final status.
+    $logFile  = '/tmp/nebuleair_firmware_update.log';
+    $doneFile = '/tmp/nebuleair_firmware_update.done';
 
-    // Cleanup (also done in script, but just in case)
-    shell_exec("rm -rf $tmp_dir");
+    @file_put_contents($logFile, '');
+    @unlink($doneFile);
+
+    // Note: $source_dir is escaped because it can contain a version-derived folder name.
+    // $tmp_dir is removed by the script itself (Step 7) but we also clean here as a safety net
+    // — done AFTER the script finishes, so we chain it inside the background block.
+    $cmd = '(sudo /var/www/nebuleair_pro_4g/update_firmware_from_file.sh '
+         . escapeshellarg($source_dir) . ' > '
+         . escapeshellarg($logFile) . ' 2>&1; '
+         . 'echo "EXIT_CODE=$?" >> ' . escapeshellarg($logFile) . '; '
+         . 'rm -rf ' . escapeshellarg($tmp_dir) . '; '
+         . 'touch ' . escapeshellarg($doneFile) . ') > /dev/null 2>&1 &';
+    shell_exec($cmd);
 
     echo json_encode([
         'success' => true,
-        'output' => $output,
+        'started_at' => time(),
         'old_version' => $old_version,
-        'new_version' => $new_version,
-        'timestamp' => date('Y-m-d H:i:s')
+        'new_version' => $new_version
     ]);
     exit;
 }