Bin commands into non-overlapping windows of width
max(ESCALATION_WINDOW_MIN_S, duration_s / ESCALATION_WINDOW_TARGET).
CV of per-window counts + zero-window fraction classify bursty /
sustained / erratic. v0.1; corpus re-tune deferred.
Bucket ctx.duration_s against SESSION_DURATION_SHORT_MAX (60s) /
MEDIUM_MAX (600s) / LONG_MAX (3600s); else marathon. Direct
measurement, confidence 0.85. Skip emission only when no commands
and zero duration. New _features/temporal.py module opens Phase E.
