An idle live stream whose connection dies without an error (airplane mode
cutting the radio) left the net-state machine stuck "online": the streaming
fetch neither errored nor delivered, no unary call was made, and the OS
`navigator` offline hint is unreliable in the Telegram/VK WebViews — so the
"Connecting…"/offline state only surfaced on the next foreground resync, not
while idle.
The gateway already pushes a keep-alive `heartbeat` every 10s, so add a
client-side watchdog (streamwatchdog.ts) that resets on every delivered event
and, after ~25s of silence, treats the stream as dropped (reportOffline +
reconnect). It is background-aware (paused while suspended) so a throttled
foreground return does not false-trip. The mock client mirrors the heartbeat
so an idle e2e session stays online.
Ilia Denisov