perf: gate daily quality sweep to off-peak hours (18:00-23:59 local) (#5131)

* perf: gate daily quality sweep to off-peak hours (18:00-23:59 local)

Anthropic doubles token allowance during off-peak (6 PM-12 AM UK time).
Quality sweep findings trigger LLM worker dispatch via the pulse, so
landing findings in this window means resulting workers also run at 2x
rates. Health issues and person stats continue on their existing
15-min/hourly cadence unaffected.

Override with QUALITY_SWEEP_OFFPEAK=0 to force daytime runs.

* chore: log when quality sweep is deferred by off-peak gate

Addresses CodeRabbit nitpick — adds visibility into why sweeps
don't run during daytime hours.

Author: marcusquinn

.agents/scripts/stats-functions.sh

@@ -889,6 +889,21 @@ update_health_issues() {
 # actionable GitHub issues for findings that warrant fixes.
 #######################################
 run_daily_quality_sweep() {
+	# Time-of-day gate — only run during off-peak hours (18:00-23:59 local).
+	# Anthropic doubles token allowance during off-peak (6 PM-12 AM UK time),
+	# and model demand is lower. Quality sweep findings trigger LLM worker
+	# dispatch via the pulse, so landing findings in this window means the
+	# resulting workers also run at 2x rates. Override: QUALITY_SWEEP_OFFPEAK=0
+	if [[ "${QUALITY_SWEEP_OFFPEAK:-1}" == "1" ]]; then
+		local current_hour
+		current_hour=$(date +%H)
+		current_hour=$((10#$current_hour)) # strip leading zero for arithmetic
+		if [[ "$current_hour" -lt 18 ]]; then
+			echo "[stats] Quality sweep deferred: hour ${current_hour} is outside off-peak window (18:00-23:59)" >>"$LOGFILE"
+			return 0
+		fi
+	fi
+
 	# Timestamp guard — run at most once per QUALITY_SWEEP_INTERVAL
 	if [[ -f "$QUALITY_SWEEP_LAST_RUN" ]]; then
 		local last_run