Two of the three findings; the third is answered in the PR thread.
**A replaced client could still enqueue.** The one-shot sweep only rejected what
was already queued, but the outgoing `InspectorClient` disconnects
asynchronously and can enqueue during its own teardown — and that late entry
would be rendered by a factory bound to the REPLACEMENT client, reading its
resource and answering through a different server. Requests now belong to a
session: each constructed client gets one, closing it rejects that session's
entries AND refuses anything it queues afterwards, and another session's
entries are untouched.
**The advertisement no longer has to guess.** Whether a sandbox exists is only
known once `/api/config` resolves, and the answer is baked into the client at
construction — guessing "available" over-claims, guessing "unavailable" strands
the whole session on the native form despite having a sandbox. The connect path
now awaits that fetch (already in flight since mount, so no human ever waits;
it only orders a deep-link auto-connect racing the same page load), after which
an absent `sandboxUrl` means confirmed-absent.
Signed-off-by: cliffhall <cliff@futurescale.com>