Stats: range buttons follow the retention settings

The Statistics page offers only the ranges kept (longest of the minute,
hour and day retentions), adds 1y and 2y when the daily data covers them,
caps the heatmap at the hourly retention and links to Explore within
retention.queries. Status and explore send retention_seconds. The query
log error names stats.retention.queries.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/stats/explore.go

@@ -8,7 +8,7 @@ import (
 )
 
 // Exploring the query log (docs/stats.md#exploring): every answer of the
-// last days (stats.query_retention), filtered by any mix of client, name,
+// last days (stats.retention.queries), filtered by any mix of client, name,
 // view, type, result and blocking, broken down by each of them.
 
 // ExploreFilter narrows the query log. Empty fields don't filter. Each
@@ -47,8 +47,9 @@ type Exploration struct {
 	Recent []QueryRow `json:"recent"`
 	// Oldest is the first answer the query log still has.
 	Oldest *time.Time `json:"oldest,omitempty"`
-	// Retention is how long it keeps them.
-	Retention string `json:"retention"`
+	// Retention is how long it keeps them, also in seconds.
+	Retention        string `json:"retention"`
+	RetentionSeconds int64  `json:"retention_seconds"`
 }
 
 // ExplorePoint is one step of the series.
@@ -59,7 +60,7 @@ type ExplorePoint struct {
 }
 
 // ErrNoQueryLog is returned when the query log is off.
-var ErrNoQueryLog = fmt.Errorf("the query log is off: it needs stats.query_log and a stats.query_retention above 0 in /etc/jarl/jarl.yaml (docs/stats.md#exploring)")
+var ErrNoQueryLog = fmt.Errorf("the query log is off: it needs stats.query_log and a stats.retention.queries above 0 in /etc/jarl/jarl.yaml (docs/stats.md#exploring)")
 
 // values splits a filter field into the values it must be one of and the
 // ones (written !VALUE) it must not be: "10.0.0.5, !10.0.0.9".
@@ -178,7 +179,7 @@ func (q *Querier) Explore(ctx context.Context, f ExploreFilter, topN, recent int
 	}
 	from := now.Add(-since).Unix()
 	out := &Exploration{From: time.Unix(from, 0), To: now, By: map[string][]Entry{}, Series: []ExplorePoint{}, Recent: []QueryRow{},
-		Retention: humanDuration(q.Opts.RetainQueries)}
+		Retention: humanDuration(q.Opts.RetainQueries), RetentionSeconds: int64(q.Opts.RetainQueries / time.Second)}
 	cond, args := q.where(f, from)
 	db := q.Store.db