The Tasks page lost the it/s indicator under load: when the engine is too busy to
report its own task, the front showed a synthetic in-flight task with rate 0. Now
the front counts SSE "data:" events (~one token each for chat/text) as it relays
the stream and publishes step + rate (tokens/s, refreshed ~2×/s) onto the in-flight
metadata, so the synthesized task shows a live it/s even while the engine can't
answer its own /admin/api/tasks. Only for streaming 200 responses; the engine's
real task (with its own rate) still wins via the (engine,model) dedup when reachable.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>