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/driver/updateDriverFromAdmin.php

@@ -72,6 +72,7 @@ try {
         jsonError("No records updated or driver not found.");
     }
 } catch (PDOException $e) {
-    jsonError("Error updating record: " . $e->getMessage());
+    error_log("[updateDriverFromAdmin.php] " . $e->getMessage());
+    jsonError("An internal error occurred. Please try again later.");
 }
 ?>