Add send-log retention days to panel Settings.

Global administrators can set delivery journal retention (7-365 days) in SQLite;
SEND_LOG_RETENTION_DAYS seeds the initial default and the log-tailer re-reads
the value every prune cycle without a restart.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/logtail/retention_test.go

@@ -0,0 +1,83 @@
+package logtail
+
+import (
+	"context"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/mixeme/selfpost/internal/store"
+)
+
+type retentionProbeStore struct {
+	mu     sync.Mutex
+	cutoff time.Time
+}
+
+func (s *retentionProbeStore) UpdateStatus(string, string, string) (int64, error) {
+	return 0, nil
+}
+
+func (s *retentionProbeStore) ListQueuedOlderThan(time.Time) ([]store.QueuedDelivery, error) {
+	return nil, nil
+}
+
+func (s *retentionProbeStore) DeleteSendLogBefore(cutoff time.Time) (int64, error) {
+	s.mu.Lock()
+	s.cutoff = cutoff
+	s.mu.Unlock()
+	return 0, nil
+}
+
+func (s *retentionProbeStore) LogtailState(string) (store.LogtailState, bool, error) {
+	return store.LogtailState{}, false, nil
+}
+
+func (s *retentionProbeStore) SaveLogtailState(string, store.LogtailState) error {
+	return nil
+}
+
+func (s *retentionProbeStore) lastCutoff() time.Time {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.cutoff
+}
+
+// retentionLoop must re-read the configured window every cycle so a panel
+// change takes effect without restarting the process.
+func TestRetentionLoopUsesUpdatedValue(t *testing.T) {
+	old := retentionInterval
+	retentionInterval = 20 * time.Millisecond
+	t.Cleanup(func() { retentionInterval = old })
+
+	var days atomic.Int32
+	days.Store(30)
+
+	st := &retentionProbeStore{}
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	go retentionLoop(ctx, st, func() int { return int(days.Load()) })
+
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if age := time.Since(st.lastCutoff()); age < 31*24*time.Hour && age > 29*24*time.Hour {
+			break
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	if age := time.Since(st.lastCutoff()); age < 29*24*time.Hour || age > 31*24*time.Hour {
+		t.Fatalf("first prune cutoff age %v, want about 30 days", age)
+	}
+
+	days.Store(7)
+	deadline = time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if age := time.Since(st.lastCutoff()); age < 8*24*time.Hour && age > 6*24*time.Hour {
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	age := time.Since(st.lastCutoff())
+	t.Fatalf("second prune cutoff age %v, want about 7 days", age)
+}