release: 1.6.0: 30-day send stats and optional auto level-2 rate limits

30-day sending statistics per domain and application, plus optional auto level-2 rate limits derived from average send rate.
Added:
  - Domain page **Sending statistics** card: total messages, peak and average
  - Level-2 rate limit **Manual** / **Auto** mode on domain and application
  - Domain export JSON now includes rate limits (`mode`, `auto_multiplier`,
Changed:
  - Auto mode uses the level-1 window (`RATE_LIMIT_WINDOW_SECONDS`); manual

Full detail: CHANGELOG.md (1.6.0).

cmd/panel/main.go

@@ -254,7 +254,7 @@ func run() error {
 	}
 
 	var wg sync.WaitGroup
-	errc := make(chan error, 3)
+	errc := make(chan error, 4)
 
 	roles := []struct {
 		name string
@@ -272,6 +272,10 @@ func run() error {
 				return days
 			})
 		}},
+		{"rate-limit-recalc", func(ctx context.Context) error {
+			runAutoRateLimitRecalc(ctx, cfg, st)
+			return nil
+		}},
 	}
 
 	for _, r := range roles {

cmd/panel/ratelimit_recalc.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"github.com/mixeme/selfpost/internal/logtail"
+	"github.com/mixeme/selfpost/internal/store"
+)
+
+// runAutoRateLimitRecalc recomputes auto-mode level-2 limits on the same
+// interval as send-log retention pruning (6 hours).
+func runAutoRateLimitRecalc(ctx context.Context, cfg config, st *store.Store) {
+	recalc := func() {
+		retention := cfg.retentionDays
+		if days, err := st.GetSendLogRetentionDays(cfg.retentionDays); err == nil {
+			retention = days
+		}
+		l1Max := cfg.rateLimitMessagesPerIP
+		if l1Max <= 0 {
+			l1Max = 100
+		}
+		l1Window := cfg.rateLimitWindowSeconds
+		if l1Window <= 0 {
+			l1Window = 3600
+		}
+		n, err := st.RecalcAllAutoRateLimits(retention, l1Max, l1Window)
+		if err != nil {
+			log.Printf("auto rate-limit recalc: %v", err)
+			return
+		}
+		if n > 0 {
+			log.Printf("auto rate-limit recalc: updated %d limit(s)", n)
+		}
+	}
+
+	recalc()
+	t := time.NewTicker(logtail.RetentionInterval())
+	defer t.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-t.C:
+			recalc()
+		}
+	}
+}