Rebuild: post a batch early when 100k files wait; log failing stats refreshes

A picture group's 500k articles made batches over the server's 256 MB
body limit: HTTP 413, the range given back and leased again in a loop
(148597: 39 times in 30 minutes). The worker now also posts once
100,000 completed or edge-cut files wait (RangeIndexer.pending).
A stats refresh that failed kept the previous totals silently; it
logs the error now.

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

app/services/search_service.ts

@@ -1,4 +1,5 @@
 import db from '@adonisjs/lucid/services/db'
+import logger from '@adonisjs/core/services/logger'
 import NzbService from '#services/nzb_service'
 
 export type SortOrder = 'newest' | 'oldest' | 'largest' | 'files' | 'name'
@@ -192,6 +193,7 @@ class SearchService {
           this.statsCache = { at: Date.now(), value }
         })
         .catch((error) => {
+          logger.warn(`Stats: ${error.message}`)
           if (!this.statsCache) throw error
         })
         .finally(() => {