fix(util): quote top-level strings in util.format %o/%O (Node parity) (#5106)

`util.format("%o", "hello")` / `console.log("%o", str)` printed the
string unquoted (`hello`) where Node renders it through `util.inspect`
(`'hello'`). The `%o`/`%O` arms called `format_jsvalue(val, 0)`, which
mirrors the bare `console.log(str)` behavior of leaving a *top-level*
string unquoted — but `%o`/`%O` should inspect the value, and inspect
quotes strings at every depth (nested strings already quoted correctly,
e.g. `%o` of `{a:"x"}` → `{ a: 'x' }`).

Route the `%o`/`%O` argument through a new `inspect_format_arg` helper
that mirrors `js_util_inspect`'s top-level handling: a primitive string
becomes `'<escaped>'`; everything else goes through `format_jsvalue`.

Verified vs Node v26.3.0: `%o`/`%O` of a string now yield `'hello'`;
numbers/objects/arrays/null/bool unchanged; `%s` still coerces without
quotes. Existing formatting/inspect unit tests pass (12).

(Out of scope: Node's `%o` also sets `showHidden`, so an array prints
`[ 1, 'two', [length]: 2 ]`; matching the `[length]` internal-slot
rendering is a separate showHidden-array feature and left as-is.)

Co-authored-by: Ralph Küpper <ralph2@skelpo.com>

Author: proggeramlug

crates/perry-runtime/src/builtins/formatting/util_format.rs

@@ -112,6 +112,22 @@ unsafe fn util_format_json_object_has_cycle(ptr: *const u8, stack: &mut Vec<usiz
     found
 }
 
+/// Render a `%o`/`%O` argument the way `util.inspect` does at the top
+/// level: a primitive string is **quoted** (`'hello'`), matching
+/// `js_util_inspect`. `format_jsvalue` alone leaves a top-level string
+/// unquoted (the `console.log(str)` bare-string behavior), so calling it
+/// directly for `%o`/`%O` diverged from Node, which routes the value
+/// through `util.inspect` (strings quoted at every depth).
+fn inspect_format_arg(val: f64) -> String {
+    let jv = crate::value::JSValue::from_bits(val.to_bits());
+    if jv.is_any_string() {
+        let s = jsvalue_string_content(val).unwrap_or_default();
+        format!("'{}'", escape_string(&s))
+    } else {
+        format_jsvalue(val, 0)
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn js_util_format(arr_ptr: *const crate::array::ArrayHeader) -> f64 {
     use crate::value::JSValue;
@@ -324,12 +340,12 @@ pub extern "C" fn js_util_format(arr_ptr: *const crate::array::ArrayHeader) -> f
                     let _depth_guard = InspectDepthLimitGuard::new(4);
                     let _hidden_guard = InspectShowHiddenGuard::new(true);
                     let _proxy_guard = InspectShowProxyGuard::new(true);
-                    out.push_str(&format_jsvalue(val, 0));
+                    out.push_str(&inspect_format_arg(val));
                 }
                 b'O' => {
                     // `%O` keeps the default depth cap (2) — matching
                     // Node's `util.inspect` default options.
-                    out.push_str(&format_jsvalue(val, 0));
+                    out.push_str(&inspect_format_arg(val));
                 }
                 b'c' => {
                     // Browser/Node console style marker. Consume the CSS