Spotnet import, header backfill, staging and counter grouping, faster search

Spotnet (CONCEPT D29):
- Index free.pt fully and import spots with their descriptions, categories
  and NZBs; a spot renames its release, since Spotnet names are more
  trustworthy than names derived from subjects.
- Find passwords in spot descriptions too, and tell "needs a password we
  have" from "needs a password we don't have".

Content inspection:
- List the contents of 7z (.7z.001) archives, SFV sets, nicovideo uploads
  and other archive-like files; mark yEncBin .bin containers as encrypted.
- Take real names from yEnc headers for randomly named files, and merge
  uploads that were split across posts.

Storage (D31, D32):
- Store segment lists zstd-compressed behind the FileStore accessor.
- group:backfill indexes older headers at low priority and pauses when
  the NVMe or HDD part of the database gets too large.

Grouping (D35, D36):
- Lone header segments wait in staged_segments until a second segment of
  their file arrives, which drops the per-article junk binaries.
- Counter grouping joins random-subject uploads by poster, [i/M] counter,
  part count and day.

Search and maintenance (D33, D34):
- A trigram-indexed search_text column, smaller indexes, estimated stats.
- Passes that clean up nonsense names; weekly index maintenance; GC budgets
  per kind.
- Web UI: grey out stale results while a search runs and cancel superseded
  requests. Count only up to 1,000 matches for the page, which made filter
  clicks take seconds (Newznab keeps the 10,000 cap).

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

commands/IndexScheduler.ts

@@ -7,6 +7,7 @@ import indexerConfig from '#config/indexer'
 import Shutdown from '#services/Shutdown'
 import FetchRangeService from '#services/FetchRangeService'
 import SplitService from '#services/SplitService'
+import BackfillService from '#services/BackfillService'
 
 export default class IndexScheduler extends BaseCommand {
   public static commandName = 'index:scheduler'
@@ -107,9 +108,19 @@ export default class IndexScheduler extends BaseCommand {
       }
     }
 
+    const backfill = async () => {
+      try {
+        const queued = await BackfillService.tick()
+        if (queued > 0) this.logger.info(`Queued ${queued} backfill range(s).`)
+      } catch (err: any) {
+        this.logger.error(`Error queuing backfill: ${err.message}`)
+      }
+    }
+
     // Run immediately, then wait a full interval after each run so runs never overlap.
     while (!Shutdown.requested) {
       await schedule()
+      await backfill()
       await split()
       await Shutdown.sleep(indexerConfig.intervalMs)
     }