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- Web UI: grey out stale results while a search runs and cancel superseded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>

app/services/Par2Service.ts

@@ -1,4 +1,5 @@
 import db from '@adonisjs/lucid/services/db'
+import type { Segment } from '#lib/nzb/index'
 import logger from '@adonisjs/core/services/logger'
 import NntpService from '#services/NntpService'
 import IngestService, { PAR2_MATCH_WINDOW_SECONDS } from '#services/IngestService'
@@ -35,11 +36,9 @@ class Par2Service {
    * Reads a par2 file whose first segment is already decoded, downloading the
    * remaining parts if there are any. Returns null when it is not par2.
    */
-  async read(first: Buffer, messageIds: Record<string, { id: string }>): Promise<Par2Set | null> {
+  async read(first: Buffer, segments: Segment[]): Promise<Par2Set | null> {
     if (!isPar2(first)) return null
-    const ids = Object.entries(messageIds)
-      .sort(([a], [b]) => Number(a) - Number(b))
-      .map(([, part]) => part.id)
+    const ids = segments.map((part) => part.id)
     if (ids.length > MAX_PARTS) return null
     if (ids.length === 1) return parsePar2(first)
 
@@ -143,9 +142,11 @@ class Par2Service {
       )
 
       // The set may have joined a release named after one random filename.
-      let releaseName = (await trx.from('releases').where('id', releaseId).first())?.name
+      const release = await trx.from('releases').where('id', releaseId).first()
+      let releaseName = release?.name
       const better = par2ReleaseName(set.files.map((f) => f.name))
-      if (releaseName && better && isBetterName(releaseName, better)) {
+      // A spot's title is kept (CONCEPT.md D29).
+      if (releaseName && better && release.source !== 'spot' && isBetterName(releaseName, better)) {
         await trx.from('releases').where('id', releaseId).update({ name: better })
         releaseName = better
       }