GHSA-PR2W-4GPJ-CPQ4 Twig: Sandbox: multiple `__toString()` policy bypasses via unguarded string coercion points

Description SandboxNodeVisitor enforces SecurityPolicy::checkMethodAllowed for implicit toString calls by wrapping selected AST nodes in CheckToStringNode. The set of wrapped nodes is incomplete, and several Twig language constructs still trigger PHP string coercion on a Stringable operand withou...