fix(js): console.log(Error) must not trigger Error.prepareStackTrace

deviceandbrowserinfo.com detects CDP by setting Error.prepareStackTrace as a spy, then calling console.log(new Error()). _consoleFn accessed a.stack, which fires prepareStackTrace if set. Fix: save/clear/restore around the .stack access.

crates/obscura-js/src/runtime.rs

@@ -2452,6 +2452,21 @@ mod tests {
         );
     }
 
+    #[test]
+    fn console_log_error_does_not_trigger_prepare_stack_trace() {
+        let mut rt = setup_runtime("<div></div>");
+        let result = rt.evaluate(r#"
+            let called = false;
+            const saved = Error.prepareStackTrace;
+            Error.prepareStackTrace = function() { called = true; return saved; };
+            const e = new Error("test");
+            console.log(e);
+            Error.prepareStackTrace = saved;
+            return called;
+        "#).unwrap();
+        assert_eq!(result, serde_json::json!(false));
+    }
+
     #[test]
     fn element_aria_reflection_setters_write_through() {
         let mut rt = setup_runtime(r#"<div id="d"></div>"#);