Rebuild: first end-to-end runs; prefetch per chunk, executable rule, wire fixes

End to end on the workstation (coordinator:run, the API, edge:node, real
NNTP): a.b.e-book.french and a.b.cd.image.playstation2.dvdiso ranges.

- Prefetcher: every connection takes the next missing chunk (leased
  ranges first, in order); one connection per range (~26k lines/s) kept
  the worker waiting
- executable rule: releases of bare executables (malware floods named
  after films and software) are dropped; they were 92% of the catalog rows
  of the test ranges, 21% of the segments
- fragments per file (details once) and gzipped batch bodies; the JSON
  limit (1 MB by default) raised to 256 MB, empty strings kept (a rule
  count's key is '')
- release_chunks.batch_from is a bigint (boneless article numbers)
- tests get their own database; edge:bench --store times BatchStore:
  1.3 s for a boneless range (1.24 ms per release chunk)

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

tests/functional/node_api.spec.ts

@@ -19,6 +19,8 @@ function chunk(at: number): Buffer {
   const lines = [1, 2].map(
     (n) => `${at + n - 1}\tSome.Show.S01E0${at % 7} [1/1] - "Some.Show.S01E0${at % 7}.1080p.mkv" yEnc (${n}/2)\tp <p@x>\tMon, 05 Oct 2026 10:00:00 +0000\t<a${at}-${n}@test>\t\t700000\t5000\tXref: news.example ${GROUP}:${at + n - 1}`
   )
+  // An obfuscated subject: counted under the key '' (which must survive the body parser).
+  lines.push(`${at + 2}\tobfuscated\tp <p@x>\tMon, 05 Oct 2026 10:00:00 +0000\t<o${at}@test>\t\t700000\t5000\tXref: news.example ${GROUP}:${at + 2}`)
   return deflateSync(Buffer.from(lines.join('\r\n') + '\r\n'))
 }
 
@@ -75,6 +77,8 @@ test.group('Node API', (group) => {
     // The same batch again: refused.
     ;(await client.post(`/api/v1/node/ranges/${rangeId}/batches`).bearerToken(token).json(batch)).assertStatus(409)
 
+    assert.deepEqual((await db.from('rule_counts').where('range_id', rangeId)).map((c) => [c.rule, c.key, Number(c.articles)]), [['obfuscated', '', 3]])
+
     ;(await client.post(`/api/v1/node/ranges/${rangeId}/finish`).bearerToken(token)).assertStatus(200)
     const range = await db.from('ranges').where('id', rangeId).first()
     assert.equal(range.status, 'done')