fix: polish two Hermes follow-up cosmetics (invalid-selector wording, empty url glob)

- invalid CSS selector now errors "Invalid selector '<sel>': <reason>" instead of
  the misleading "Element not found" — the coordinate path (resolve_by_selector)
  now also inspects exception_details, matching resolve_element_object_id.
- `wait --url ""` is rejected at parse time ("needs a non-empty pattern") rather
  than silently matching any URL. Unit test added.

Not changed: verb-less `find role X` defaulting to a click. That default is a
deliberate, tested decision (test_find_role_default_subaction_click_when_no_action);
changing it to locate-and-report is a design choice left to the maintainer.

cli/src/native/element.rs

@@ -845,6 +845,12 @@ async fn resolve_by_selector(
         )
         .await?;
 
+    // A syntactically-invalid CSS selector makes querySelector throw — surface
+    // that as "invalid selector" rather than a misleading "element not found".
+    if let Some(ex) = result.exception_details {
+        return Err(format!("Invalid selector '{}': {}", selector, ex.text));
+    }
+
     let val = result.result.value.unwrap_or(Value::Null);
     let x = val.get("x").and_then(|v| v.as_f64());
     let y = val.get("y").and_then(|v| v.as_f64());