The whole point of keeping the meter connection in a hash of its own was
that not a line of the generic and solarEdge vendors would change.
Checks it rather than claiming it: a stored solarEdge connection, whose
behaviour no suite covered until now, must still end up with exactly one
connection, as must a generic one.
Also records the connection a discovery came from in
processDiscoveryResult() rather than in the discoveryFinished handler.
The initial setup calls it from a second handler on the same signal, so
recording it there made the orphan sweep depend on the order Qt happens
to invoke the two.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>