fix: address Copilot review round 1 (#2333)

A runner that threw ETIMEDOUT landed in the catch and read as
unavailable, bypassing the split the previous commit added. The thrown
error is now normalized onto the `{ error }` path so the timeout check
covers both shapes; a test pins the thrown case.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PsmUAZ6aLUAFqenjJKSSRp
Signed-off-by: cliffhall <cliff@futurescale.com>

scripts/lib/pty.test.mjs

@@ -189,6 +189,15 @@ test("probeScriptVersion throws on a timed-out probe instead of reporting no scr
       probeScriptVersion(() => ({ error: timedOut, stdout: "", stderr: "" })),
     new RegExp(`did not exit within ${SCRIPT_PROBE_TIMEOUT_MS}ms`),
   );
+  // A runner that THROWS the same error is normalized onto the same path — the
+  // `catch` must not quietly turn a thrown ETIMEDOUT back into "unavailable".
+  assert.throws(
+    () =>
+      probeScriptVersion(() => {
+        throw timedOut;
+      }),
+    /did not exit within/,
+  );
   // And it reaches the caller: resolvePtyWrapper must not turn it into a skip.
   assert.throws(
     () =>