When a user renames their tunnel subdomain, the upsert (onConflict=user_id)
overwrote the tunnels row in place, but the old subdomain's Redis
tunnel:active:<sub> flag was never cleared. The edge tunnel-active gate kept
serving the stale flag for up to its ~30s TTL, after which it fell back to a
Postgres miss and (currently) returned a misleading suspended response.
Capture the user's previous subdomain before the upsert and, when it changes,
DEL the old kill-switch key (new clearTunnelActive helper) so the edge gate
immediately stops treating the old subdomain as a live tunnel.
Gerhard Scheikl