fix(hub): keep an unmatched admin_challenge visible, add trace logging

A real report showed audio_root timing out with *nothing* logged in
between the connection handshake and the timeout — no admin_challenge, no
error, nothing. The previous fix made an unmatched admin_challenge return
silently (correctly, to stop it stealing an unrelated pending request —
see the earlier commit), but that silence is indistinguishable from "the
request never reached the node at all", which is exactly the ambiguity
blocking this investigation. An unmatched admin_challenge is now logged
(op, op_id, and the full set of currently-pending keys) instead of
dropped quietly, and setAudioRoot/_authorizeAdminOp trace both hops of
the round trip explicitly. Node-side, _do_audio_root gets a debug log at
entry — cheap, and the only way to know from server logs alone whether
the request was ever received if the client-side trail comes up empty.

Diagnostic only: no routing behavior changed from the previous fix,
verified against the same reproduction script.

0 files changed, 0 insertions, 0 deletions