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- Web UI: grey out stale results while a search runs and cancel superseded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/unit/nicovideo.spec.ts

@@ -0,0 +1,46 @@
+import { test } from '@japa/runner'
+import { randomBytes } from 'node:crypto'
+import { zstdCompressSync, constants } from 'node:zlib'
+import { NICOVIDEO_FILE, nicovideoInfo, nicovideoReleaseName, zstdPrefix } from '#lib/content/index'
+
+function tarEntry(name: string, data: Buffer): Buffer {
+  const header = Buffer.alloc(512)
+  header.write(name, 0, 'utf8')
+  header.write(data.length.toString(8).padStart(11, '0') + '\0', 124, 'latin1')
+  header.write('ustar\0', 257, 'latin1')
+  return Buffer.concat([header, data, Buffer.alloc((512 - (data.length % 512)) % 512)])
+}
+
+test.group('nicovideo captures', () => {
+  test('reads the title from the start of a capture, even a truncated one', async ({ assert }) => {
+    const dir = '1790720489_nicovideo_jp_watch_sm27965722'
+    const response = {
+      data: {
+        metadata: { jsonLds: [{ author: { name: 'まふまふ' } }] },
+        response: {
+          video: { id: 'sm27965722', title: '桜花ニ月夜ト袖シグレ／After the Rain【そらる×まふまふ】', registeredAt: '2016-01-08T20:00:00+09:00' },
+          owner: { nickname: 'まふまふ' },
+          tag: { items: [{ name: '音楽' }, { name: 'After_the_Rain' }] },
+        },
+      },
+    }
+    const tar = Buffer.concat([
+      tarEntry(`${dir}/`, Buffer.alloc(0)),
+      tarEntry(`${dir}/server_response.metadata`, Buffer.from(JSON.stringify(response, null, 2))),
+      tarEntry(`${dir}/01.cmfa`, randomBytes(300_000)),
+    ])
+    const compressed = zstdCompressSync(tar, { params: { [constants.ZSTD_c_compressionLevel]: 3 } })
+    // Only the first part of the stream, as in the file's first article.
+    const info = nicovideoInfo(await zstdPrefix(compressed.subarray(0, Math.floor(compressed.length * 0.6))))!
+    assert.deepEqual(info, {
+      id: 'sm27965722',
+      title: '桜花ニ月夜ト袖シグレ／After the Rain【そらる×まふまふ】',
+      owner: 'まふまふ',
+      registeredAt: '2016-01-08T20:00:00+09:00',
+      tags: ['音楽', 'After_the_Rain'],
+    })
+    assert.equal(nicovideoReleaseName(info, 'sm1'), '桜花ニ月夜ト袖シグレ／After the Rain【そらる×まふまふ】 - まふまふ (nicovideo sm27965722)')
+    assert.equal(NICOVIDEO_FILE.exec(`${dir}.tar.zst`)![1], 'sm27965722')
+    assert.isNull(nicovideoInfo(await zstdPrefix(Buffer.from('not zstd'))))
+  })
+})