✨ feat(user): magic-link expired-token cleanup loop (ADR-0028 Phase A consequence) (#65)

Co-authored-by: Gabriel Radureau <arcodange@gmail.com>
Co-committed-by: Gabriel Radureau <arcodange@gmail.com>

pkg/user/magic_link_cleanup.go

@@ -0,0 +1,56 @@
+package user
+
+import (
+	"context"
+	"time"
+
+	"github.com/rs/zerolog/log"
+)
+
+// MagicLinkCleanupRunner periodically deletes expired magic-link tokens
+// (ADR-0028 Phase A consequence — the rows accumulate without cleanup
+// otherwise, and stale rows are pure overhead since the token plaintext
+// is never stored).
+type MagicLinkCleanupRunner struct {
+	repo MagicLinkRepository
+}
+
+// NewMagicLinkCleanupRunner creates a new cleanup runner.
+func NewMagicLinkCleanupRunner(repo MagicLinkRepository) *MagicLinkCleanupRunner {
+	return &MagicLinkCleanupRunner{repo: repo}
+}
+
+// StartCleanupLoop runs the cleanup pass every `interval`. Stops when ctx
+// is cancelled. interval <= 0 disables the loop.
+func (r *MagicLinkCleanupRunner) StartCleanupLoop(ctx context.Context, interval time.Duration) {
+	if interval <= 0 {
+		return
+	}
+	go func() {
+		ticker := time.NewTicker(interval)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				_, _ = r.runOnce(ctx)
+			}
+		}
+	}()
+}
+
+// runOnce performs a single cleanup pass. Returns the count of deleted rows.
+// Exposed for testing — tests drive runOnce directly instead of waiting on
+// the ticker.
+func (r *MagicLinkCleanupRunner) runOnce(ctx context.Context) (int64, error) {
+	n, err := r.repo.DeleteExpiredMagicLinkTokens(ctx, time.Now())
+	if err != nil {
+		log.Error().Ctx(ctx).Err(err).Msg("magic-link cleanup: delete failed")
+		return 0, err
+	}
+	if n > 0 {
+		log.Trace().Ctx(ctx).Int64("deleted", n).Msg("magic-link cleanup: removed expired tokens")
+	}
+	return n, nil
+}