Long sessions died when a single transient blip flipped the app to offline and
the queue then skipped every cached-but-not-downloaded track. Harden the
detector:
- Consecutive-failure hysteresis: declare offline only after 2 failed polls,
not a single blip.
- Replace the HEAD https://1.1.1.1 probe with a concurrent race of cheap
generate_204 endpoints, so a saturated link (long Hi-Res tracks) no longer
times the probe out.
- Positive liveness override: if a segment downloaded within the last 45s we
are online by definition, regardless of the probe.
cc
vicrodh
133e90f752