Complete archive listings by walking RAR headers, at low priority

Inspection lists only the entries whose headers are in the first segment
of a first volume. A walk hops from header to header, fetching one segment
per entry and volume, in its own queue (one job per collection worker) on
NNTP connections inspection isn't waiting for. content:walk-archives queues
releases inspected earlier (CONCEPT D40).

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

commands/workers/Collection.ts

@@ -7,6 +7,7 @@ import Shutdown from '#services/Shutdown'
 import QueueService from '#services/QueueService'
 import NntpService from '#services/NntpService'
 import ContentService from '#services/ContentService'
+import ArchiveWalkService from '#services/ArchiveWalkService'
 import File from '#models/file'
 
 export default class CollectionWorker extends BaseCommand {
@@ -70,10 +71,28 @@ export default class CollectionWorker extends BaseCommand {
       this.logger.error(`Collection job ${job?.id} failed: ${err.message}`)
     })
 
+    // Complete archive listings (D40): background work beside inspection, on the same NNTP pool.
+    const walkConcurrency = env.get('ARCHIVE_WALK_CONCURRENCY', 1)
+    const walker = walkConcurrency > 0
+      ? new Worker('archive-walk-queue', async (job) => {
+          const o = await ArchiveWalkService.walk(Number(job.data.releaseId))
+          if (o.skipped) return o
+          this.logger.info(
+            `Archive walk of release ${o.releaseId}: ${o.before} → ${o.entries} entries from ${o.segments} segments` +
+              (o.complete ? '' : ` (stopped: ${o.stopped})`) +
+              (o.renamed ? `, renamed to "${o.renamed}"` : '')
+          )
+          return o
+        }, { connection: queueConfig.connection, concurrency: walkConcurrency })
+      : null
+    walker?.on('failed', (job, err) => {
+      this.logger.error(`Archive walk job ${job?.id} failed: ${err.message}`)
+    })
+
     this.logger.info('Collection worker started and listening for jobs.')
     await Shutdown.wait()
     this.logger.info('Shutting down: finishing active jobs...')
-    await worker.close()
+    await Promise.all([worker.close(), walker?.close()])
     await NntpService.shutdown()
     await QueueService.closeAll()
   }