v1.9.3: Fix wifi_connect (escaping shell + URL) + log dédié

Bugs corrigés:
- launcher.php passait SSID/PASS au shell sans escapeshellarg(): un
  mot de passe avec $/&/;/espace cassait silencieusement la commande
  avant que nmcli ne soit appelé. Cause probable des retours clients
  "ça bloque au cliquer sur Se connecter".
- wifi.html n'encodait pas SSID/PASS dans l'URL: caractères &/+/=
  corrompaient la requête.

Observabilité:
- Nouveau fichier logs/wifi_connect.log avec timestamps stricts
- launcher.php log la requête entrante (IP, longueurs SSID/PASS)
- connexion.sh: fonction log_wc(), snapshots NM avant/après,
  capture stdout+stderr nmcli, code retour explicite, fallback SSID
  dérivé du serial si deviceName indisponible.

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

html/launcher.php

@@ -1268,6 +1268,17 @@ if ($type == "wifi_connect") {
     $SSID=$_GET['SSID'];
     $PASS=$_GET['pass'];
 
+    // Dedicated WiFi connect log (separate from app.log for easier debugging)
+    $wifi_log = '/var/www/nebuleair_pro_4g/logs/wifi_connect.log';
+    $log_wc = function($msg) use ($wifi_log) {
+        $ts = date('Y-m-d H:i:s');
+        @file_put_contents($wifi_log, "[$ts] [launcher.php] $msg\n", FILE_APPEND);
+    };
+    $log_wc("=== wifi_connect request received ===");
+    $log_wc("SSID='" . $SSID . "' (len=" . strlen($SSID) . ")");
+    $log_wc("PASS=[HIDDEN] (len=" . strlen($PASS) . ")");
+    $log_wc("client_ip=" . ($_SERVER['REMOTE_ADDR'] ?? '?'));
+
     // Get device name and hostname for instructions
     try {
         $db = new PDO("sqlite:$database_path");
@@ -1279,13 +1290,20 @@ if ($type == "wifi_connect") {
         $db = null;
     } catch (PDOException $e) {
         $deviceName = 'NebuleAir';
+        $log_wc("WARN: PDO error reading deviceName: " . $e->getMessage());
     }
     $hostname = trim(shell_exec('hostname 2>/dev/null')) ?: 'aircarto';
+    $log_wc("deviceName='$deviceName' hostname='$hostname'");
 
-    // Launch connection script in background
+    // Launch connection script in background.
+    // CRITICAL: escapeshellarg() each argument so SSIDs with spaces or passwords
+    // with special characters ($, &, ;, etc.) are passed correctly to bash.
     $script_path = '/var/www/nebuleair_pro_4g/connexion.sh';
-    $log_file = '/var/www/nebuleair_pro_4g/logs/app.log';
-    shell_exec("$script_path $SSID $PASS >> $log_file 2>&1 &");
+    $ssid_arg = escapeshellarg($SSID);
+    $pass_arg = escapeshellarg($PASS);
+    $cmd = "$script_path $ssid_arg $pass_arg >> $wifi_log 2>&1 &";
+    $log_wc("Launching: $script_path <ssid> <pass> (background, output -> wifi_connect.log)");
+    shell_exec($cmd);
 
     // Return JSON response with instructions
     header('Content-Type: application/json');