Rebuild: a lean overview scan for the edge worker

The worker reads the XOVER reply's text directly: fields by position, the
owner from the Xref without arrays (crossposts leave before any subject
parsing), a subject parsed once per file (cached without its segment
counter), a file's details as one shared object, dates as numbers.
Garbage collection had been ~22% of the time.

Same results as parseOverviews + segmentFromHeader on 800k real lines.
edge:bench (one core): boneless 137k → 193k headers/s (CPU 21 → 12.8 s),
ath (2013) 143k → 303k; peak RSS 1.15 / 0.87 GB.

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

commands/edge_bench.ts

@@ -4,7 +4,7 @@ import { mkdir, readFile, readdir, writeFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import { unzipSync } from 'node:zlib'
 import env from '#start/env'
-import { XoverClient, parseOverviews } from '#lib/nntp/index'
+import { XoverClient } from '#lib/nntp/index'
 import { RangeIndexer } from '#lib/edge/index'
 import { DEFAULT_RULES, type Rules } from '#lib/rules/index'
 import db from '@adonisjs/lucid/services/db'
@@ -117,11 +117,9 @@ export default class EdgeBench extends BaseCommand {
       t.inflate += performance.now() - at
       text += data.length
       at = performance.now()
-      const overviews = parseOverviews(data)
-      t.parse += performance.now() - at
-      at = performance.now()
       const next = Number(file.split('-')[2].replace('.gz', '')) + 1
-      indexer.add(overviews, next)
+      // The worker's path: the reply's text straight into the indexer (parsing is part of "index").
+      indexer.addText(data, next)
       const last = file === files.at(-1)
       if (last) indexer.finish()
       t.index += performance.now() - at