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- Web UI: grey out stale results while a search runs and cancel superseded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

tests/functional/backfill.spec.ts

@@ -0,0 +1,38 @@
+import { test } from '@japa/runner'
+import db from '@adonisjs/lucid/services/db'
+import testUtils from '@adonisjs/core/services/test_utils'
+import indexerConfig from '#config/indexer'
+import BackfillService from '#services/BackfillService'
+import FetchRangeService from '#services/FetchRangeService'
+
+test.group('BackfillService', (group) => {
+  group.each.setup(() => testUtils.db().withGlobalTransaction())
+
+  test('queues header-only ranges downwards, capped, without holding back the live watermark', async ({ assert }) => {
+    const now = new Date()
+    const batch = Number(indexerConfig.batchSize)
+    const [g] = await db
+      .table('groups')
+      .insert({
+        name: 'alt.binaries.backfilltest', active: true, fetch_bodies: true, last_queued_id: 5_000_000, last_indexed_id: 5_000_000,
+        backfill_until_id: 5_000_000 - 100 * batch, backfill_next_id: 4_900_000, created_at: now, updated_at: now,
+      })
+      .returning('*')
+
+    const queued = await BackfillService.tick()
+    assert.equal(queued, indexerConfig.backfill.maxQueued)
+    const ranges = await db.from('fetch_ranges').where('group_id', g.id).orderBy('end_id', 'desc')
+    assert.isTrue(ranges.every((r) => r.backfill && r.status === 'queued'))
+    assert.equal(Number(ranges[0].end_id), 4_900_000)
+    assert.equal(Number(ranges[0].start_id), 4_900_000 - batch + 1)
+    const after = await db.from('groups').where('id', g.id).first()
+    assert.equal(Number(after.backfill_next_id), 4_900_000 - queued * batch)
+
+    // The cap holds while those wait.
+    assert.equal(await BackfillService.tick(), 0)
+
+    // Backfill ranges don't hold back the live watermark.
+    await db.from('groups').where('id', g.id).update({ last_queued_id: 5_100_000 })
+    assert.equal(await FetchRangeService.advanceWatermark({ id: g.id, name: g.name }), 5_100_000n)
+  })
+})