feat: add configurable retention period for Redis usage queue

- Introduced `redis-usage-queue-retention-seconds` config parameter with a default of 60 seconds and a max of 3600 seconds.
- Updated logic in `redisqueue` to honor configurable retention periods for enqueued usage data.
- Modified config validation and initialization to support and enforce retention limits.
- Enhanced change tracking in `config_diff` to detect updates to this parameter.

internal/redisqueue/queue.go

@@ -6,7 +6,10 @@ import (
 	"time"
 )
 
-const retentionWindow = time.Minute
+const (
+	defaultRetentionSeconds int64 = 60
+	maxRetentionSeconds     int64 = 3600
+)
 
 type queueItem struct {
 	enqueuedAt time.Time
@@ -20,10 +23,15 @@ type queue struct {
 }
 
 var (
-	enabled atomic.Bool
-	global  queue
+	enabled          atomic.Bool
+	retentionSeconds atomic.Int64
+	global           queue
 )
 
+func init() {
+	retentionSeconds.Store(defaultRetentionSeconds)
+}
+
 func SetEnabled(value bool) {
 	enabled.Store(value)
 	if !value {
@@ -35,6 +43,16 @@ func Enabled() bool {
 	return enabled.Load()
 }
 
+func SetRetentionSeconds(value int) {
+	normalized := int64(value)
+	if normalized <= 0 {
+		normalized = defaultRetentionSeconds
+	} else if normalized > maxRetentionSeconds {
+		normalized = maxRetentionSeconds
+	}
+	retentionSeconds.Store(normalized)
+}
+
 func Enqueue(payload []byte) {
 	if !Enabled() {
 		return
@@ -110,7 +128,11 @@ func (q *queue) pruneLocked(now time.Time) {
 		return
 	}
 
-	cutoff := now.Add(-retentionWindow)
+	windowSeconds := retentionSeconds.Load()
+	if windowSeconds <= 0 {
+		windowSeconds = defaultRetentionSeconds
+	}
+	cutoff := now.Add(-time.Duration(windowSeconds) * time.Second)
 	for q.head < len(q.items) && q.items[q.head].enqueuedAt.Before(cutoff) {
 		q.head++
 	}