Tiny-archive rule; the ladder's discard by index; the namer in chunks

The tiny-archive rule (dropTinyArchives, both indexers): a settled single
archive of one article and 2-100 kB under a release-like name, spaces
allowed, outside the exempt groups and without an e-book, subtitle,
crack, cover or sidecar word: the 2015-17 exe-stub flood in miniature,
1.66M catalog rows (LOG.md (131), (133)).

PendingLadder.discard scanned every waiting row against the dropped
signatures and classes, 9+ minutes a sweep inside the claim, stalling
every lane: now driven from the dropped classes and signatures into the
indexes. The namer feeds the indexer the span's overview text chunk by
chunk (one string of it topped V8's limit) and gives up spans over 3M
articles. Migration 7000: a partial index on the taken probe candidates
for the prober's start.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

REBUILD.md

@@ -806,9 +806,17 @@ unscrambled name without spaces and without an e-book format in it is
 dropped as a **nonsense piece** (`nonsense-piece`, key: the upload tool):
 the newznzb.* pieces (scene-styled or random with a "-XX" suffix), 9% of
 the catalog; under 100 kB are cue/log sidecars and adverts, and the names
-with spaces are books and albums. Both rules are switched by the
-rule set (`dropStubArchives`, `dropNonsensePieces`), sampled like every
-drop, and mirrored in `lib/rules/rule_set.ts` (the TypeScript indexer
+with spaces are books and albums. Below that, a settled single archive of
+one article and 2–100 kB under a release-like name (spaces allowed), outside
+the exempt groups and without an e-book, subtitle, crack/keygen/trainer,
+cover or sidecar word, is dropped as a **tiny archive** (`tiny-archive`,
+key: the upload tool; LOG.md (131), (133)): the 2015–17 flood's RARs
+holding "<title>.exe" at 2–60 kB, 1.66M catalog rows from a dozen posters
+(12 of 12 fetched fake); the word exemptions keep the real tiny archives
+(subtitles, cracks, trainers) at the price of ~50k fakes named "Incl
+Keygen" that the prober judges later. The rules are switched by the
+rule set (`dropStubArchives`, `dropNonsensePieces`, `dropTinyArchives`),
+sampled like every drop, and mirrored in `lib/rules/rule_set.ts` (the TypeScript indexer
 judges as each batch completes files, so it passes settled without the
 window's knowledge). Gone: fragments and the cut-off, `uploads_of` (online now),
 `check.ts` and the fixture comparison (the parity with the TypeScript