Field signals ts=1784019503 (heartbeat reports 0 frames during 64s
browser calibration — reads as broken but is healthy) and ts=1784042064
(1292s Windows render hard-exited during video frame extraction with
no final error string — silent worker crash).
Add calibrating/capturing state to heartbeat labels; surface synthetic
terminal error on unexpected worker exit when no explicit error was
emitted.
Stack: PR #6 of 9 (base via/overlay-count-lint).
Signed-off-by: Via <vance@heygen.com>
Via
971bcf39ae