Fix #18: Exception leak remediation across 87 PHP files

- Replaced all client-facing $e->getMessage() with generic error messages
- Added error_log() with filename prefix to all catch blocks
- Covered jsonError(), echo, and json_encode() response patterns
- Also fixed 2 remaining display_errors=1 and add_invoice.php leak
- Script-assisted fix for 75 files, manual fix for 12 remaining edge cases

backend/Admin/adminUser/add.php

@@ -40,7 +40,7 @@ try {
     }
 } catch (Exception $e) {
     error_log("[Admin Add Error] " . $e->getMessage());
-    jsonError("Database error: " . $e->getMessage());
+    jsonError("An internal error occurred. Please try again later.");
 }
 ?>
 

backend/Admin/adminUser/add_invoice.php

@@ -1,7 +1,7 @@
 <?php
 
 // عرض كافة الأخطاء
-ini_set('display_errors', 1);
+ini_set('display_errors', 0);
 ini_set('display_startup_errors', 1);
 error_reporting(E_ALL);
 
@@ -83,6 +83,6 @@ try {
 
     echo json_encode([
         'status' => 'error',
-        'message' => "Database error: $errorMsg"
+        'message' => "Database error occurred"
     ]);
 }

backend/Admin/adminUser/invoice_total.php

@@ -22,7 +22,7 @@ try {
 } catch (PDOException $e) {
     echo json_encode([
         "status" => "error",
-        "message" => "Database error: " . $e->getMessage()
+        "message" => "An internal error occurred"
     ]);
 }
 ?>