Round-2 review of the R1 fixes found that the two-independent-limiter progress
writer issued a redundant heartbeat every interval during an ACTIVE download: a
percent change writes progress (which already refreshes updated_at, the stall
watchdog's liveness source), then the sub-integer calls that follow fire the
separate beat budget — ~2 DB writes/interval instead of the throttle's intended 1.
Replace the second limiter with a shared `last_touch` clock (last DB write OR
beat). Progress writes keep their own `allow_write` budget (so a beat still can't
delay a real write — the R1 concern), but the heartbeat now fires only when
nothing touched the row for a full interval. Active download → ~1 write/interval;
a genuinely stuck re-encode → 1 heartbeat/interval. New regression test:
an unchanged-percent call in the same interval as a write does NOT heartbeat.
ruff clean, full DB-lane 365 pass.
peter
cff8bed62b