feat(api,userbot,frontend): fetch only new messages in backfill by default

frontend/src/lib/components/jobs/JobList.svelte

@@ -79,8 +79,12 @@
     schedule();
   }
 
-  function kindLabel(kind: string): string {
-    return KIND_LABELS[kind] ?? kind;
+  function kindLabel(job: JobView): string {
+    const label = KIND_LABELS[job.kind] ?? job.kind;
+    if (job.kind !== "backfill") {
+      return label;
+    }
+    return job.params.full ? `${label} (полный)` : `${label} (новые)`;
   }
 
   function processed(job: JobView): number | null {
@@ -117,7 +121,7 @@
     {#each jobs as job (job.id)}
       <div class="job">
         <div class="job-head">
-          <span class="kind">{kindLabel(job.kind)}</span>
+          <span class="kind">{kindLabel(job)}</span>
           {#if canCancel(job)}
             <button
               type="button"