Review follow-up on the watchdog rewrite:
- Register the deadline reaction inside `next()` and detach it when the
demand settles. Racing against one watchdog-lifetime promise kept every
settled race reachable through that promise's reactions, retaining each
resolved `StreamChunk` for the length of the stream: a 10,000-value probe
kept 100/100 sampled values before this change and 0/100 after.
- Take the neighboring stall case's 1,000ms idle budget in the new
transport-recovery case: the retry performs a real local HTTP/SSE round
trip, and a 50ms budget would let coverage-lane scheduling decide it.
- Document the contract where it is described: `packages/util/timeout/README`
(both languages) and the bounded-recovery and timeout-library notes no
longer claim that only the transport observes the watchdog signal.
Tianyi Cui
99670bab72