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>

config/bodyparser.ts

@@ -27,10 +27,11 @@ const bodyParserConfig = defineConfig({
    * Config for the JSON parser.
    */
   json: {
-    /**
-     * Normalize empty string values to null.
-     */
-    convertEmptyStringsToNull: true,
+    // Edge worker batches carry their releases' chunks (base64) and edge fragments; the limit is on the inflated body.
+    limit: '256mb',
+
+    // Workers send '' on purpose (e.g. a rule count's key); null would break NOT NULL columns.
+    convertEmptyStringsToNull: false,
 
     /**
      * Content types handled by the JSON parser.
@@ -66,8 +67,7 @@ const bodyParserConfig = defineConfig({
     /**
      * Maximum accepted payload size for multipart requests.
      */
-    // Edge worker batches carry their releases' chunks (a few MB, base64).
-    limit: '64mb',
+    limit: '20mb',
 
     /**
      * Content types handled by the multipart parser.