Add `reconnect_idle_retry_ms` (default 0 = legacy terminate). When > 0, the
transport loop no longer breaks permanently on Exhausted: the new
`idle_retry_after_exhausted` helper idles (shutdown-cancellable), resets the
attempt counter / backoff to base, and retries (gap #7). The real config
sets 60s. The reset happens ONLY after Exhausted plus a deliberate idle
wait, never on connect, so the issue #358 latch is untouched.
Critical cross-file coupling: `service.rs`'s `MaxReconnectAttemptsExceeded`
handler previously dropped the runtime and broke the event loop. With
idle-retry active the transport stays alive and re-emits events, so the
handler now surfaces lifecycle Exhausted to the UI but keeps the runtime and
continues the loop (only the legacy path still drops + breaks). When the
re-armed transport later reaches SessionEstablished, the existing handler
moves the lifecycle back to Connected.
Startup auto-connect now retries on a bounded, monotonic schedule
(`startup_retry_schedule` = 2s/5s/15s/30s) instead of giving up after one
failed attempt (gap #8), re-resolving the transport config each iteration.
cc
vicrodh
85a811c834