04ac8d3157
Two related bugs in connectReconnectingNestsListener:
1. Orchestrator never advanced past the first Failed. The reconnect
loop used `listener.state.collect { ... return@collect }` to
"exit" on a terminal state, but `return@collect` only returns
from the lambda — a StateFlow's collect keeps running. As a
result, after the first transport failure the orchestrator
re-entered the lambda for every subsequent emission and never
reached the outer `delay(delayMs)` / openOnce() that opens the
next session. Switch to `onEach { mirror } + first { terminal }`
so the upstream completes deterministically.
2. SubscribeHandle stopped emitting after a reconnect (the
long-deferred Tier-4 follow-up). Reissue the subscription on
every activeListener swap by feeding a wrapper-side
MutableSharedFlow from a `collectLatest` pump that re-calls
`listener.subscribeSpeaker(...)` against each fresh session.
The buffer (64 frames ≈ 1.3 s of Opus) covers a typical
re-handshake without dropping speech. Unsubscribing the
logical handle cancels the pump and forwards a best-effort
unsubscribe to the live underlying handle.
Tests: ReconnectingNestsListenerTest covers both happy-path
session swap (frames keep arriving) and the unsubscribe-before-swap
path. Uses real coroutines + Dispatchers.Default rather than
runTest because the test scheduler doesn't auto-advance the
StateFlow + delay chain reliably under UnconfinedTestDispatcher.