Statistics page: the statistics database's size, and a fullness bar on the disk tiles

The server section shows the statistics database's size (with its -wal and -shm) and how many answers the query log holds, linking to the dashboard's Storage panel; the disk tiles get the same bar as the dashboard. GET /stats/server has database {path, bytes, query_log_rows}.

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

internal/server/h_stats.go

@@ -283,6 +283,16 @@ func (s *Server) statsServer(w http.ResponseWriter, r *http.Request, p *auth.Pri
 		labels = append(labels, "statistics database")
 	}
 	out["disks"] = stats.DiskUsage(labels, dirs)
+	// The statistics database: what the statistics cost on disk.
+	if db := s.cfg.Stats.Store().Path(); db != "" && db != ":memory:" {
+		info := map[string]any{"path": db, "bytes": dbBytes(db)}
+		if keep := s.cfg.Stats.Options().RetainQueries; keep > 0 && s.cfg.Stats.Options().QueryLog {
+			if n, err := s.cfg.Stats.Store().QueryLogSize(r.Context()); err == nil {
+				info["query_log_rows"] = n
+			}
+		}
+		out["database"] = info
+	}
 	writeJSON(w, http.StatusOK, out)
 	return nil
 }