quiet-hours: configurable time-window schedule

Adds QuietHours config section (start/end as HH:MM local time). The loop's
gatherer checks the window each tick: if now falls within [start, end), the
State.QuietHours flag is set to true regardless of the config fact (which
the voice toggle writes independently). Both sources activate quiet —
schedule AND toggle.

Handles midnight-crossing windows (23:00-08:00). The gate already reads
State.QuietHours for care nudge suppression — no gate change needed.

internal/loop/gather.go

@@ -18,14 +18,22 @@ import (
 // Gatherer — holds nothing mutable; the Store is the only dependency. The
 // daemon runs one Gatherer per tick.
 type Gatherer struct {
-	store *store.Store
-	rules []Rule
+	store      *store.Store
+	rules      []Rule
+	quietStart string // "HH:MM" local time, "" = disabled
+	quietEnd   string // "HH:MM" local time, "" = disabled
 }
 
 func NewGatherer(s *store.Store, rules []Rule) *Gatherer {
 	return &Gatherer{store: s, rules: rules}
 }
 
+// SetQuietHours enables the time-window schedule check. Times are local.
+func (g *Gatherer) SetQuietHours(start, end string) {
+	g.quietStart = start
+	g.quietEnd = end
+}
+
 // GatherState — reads the store ONCE and assembles the snapshot the pure Tick
 // will operate on.
 //
@@ -116,6 +124,12 @@ func (g *Gatherer) GatherState(ctx context.Context, now time.Time) (State, []sto
 	if f, ok := readFact(ctx, g.store, "quiet_hours"); ok {
 		quiet = f.Value == "true" || f.Value == `"true"`
 	}
+	// Schedule-based quiet hours: if a time window is configured AND we're
+	// inside it, quiet is true regardless of the config fact. The voice
+	// toggle extends activation independently — both can fire at once.
+	if g.quietStart != "" && g.quietEnd != "" && inQuietWindow(now, g.quietStart, g.quietEnd) {
+		quiet = true
+	}
 	var calBusy bool
 	if f, ok := readFact(ctx, g.store, "calendar_busy"); ok {
 		calBusy = f.Value == "true" || f.Value == `"true"`
@@ -141,6 +155,38 @@ func (g *Gatherer) GatherState(ctx context.Context, now time.Time) (State, []sto
 	return s, due, nil
 }
 
+// inQuietWindow returns true when `now` falls within the daily window
+// [start, end). start/end are "HH:MM" in local time. Windows that cross
+// midnight (start > end) are handled: "23:00"-"08:00" means quiet from
+// 23:00 to 08:00 the next day.
+func inQuietWindow(now time.Time, start, end string) bool {
+	startH, startM, ok1 := parseHHMM(start)
+	endH, endM, ok2 := parseHHMM(end)
+	if !ok1 || !ok2 {
+		return false
+	}
+	nowMin := now.Hour()*60 + now.Minute()
+	startMin := startH*60 + startM
+	endMin := endH*60 + endM
+	if startMin < endMin {
+		return nowMin >= startMin && nowMin < endMin
+	}
+	// Crossing midnight: e.g., 23:00-08:00.
+	return nowMin >= startMin || nowMin < endMin
+}
+
+func parseHHMM(s string) (hour, min int, ok bool) {
+	if len(s) != 5 || s[2] != ':' {
+		return 0, 0, false
+	}
+	h := int(s[0]-'0')*10 + int(s[1]-'0')
+	m := int(s[3]-'0')*10 + int(s[4]-'0')
+	if h < 0 || h > 23 || m < 0 || m > 59 {
+		return 0, 0, false
+	}
+	return h, m, true
+}
+
 func readFact(ctx context.Context, s *store.Store, key string) (store.Fact, bool) {
 	f, err := s.LatestFact(ctx, key)
 	if err != nil {