Rebuild: phase 2's prober reads the probe queue

probe:run (compose service prober, PROBE_CONNECTIONS, default 6) claims
waiting candidates of settled releases (lone, then par2, then archive),
fetches each article with BODY over connections of its own (no
compression) and inspects it: the yEnc name and size, the content type
from the first bytes, a par2 set's files, a RAR volume's entries and
whether they're encrypted. Results per release and kind in
release_inspections (CHUNK_TABLESPACE, the HDD); on the release
passworded, inner_name (the largest content name) and inspected_at.
430 = missing, not yEnc = error, both final; connection trouble puts
the candidate back.

Fetch and parse in one process: an article takes ~0.1 s per connection,
parsing a few ms (no queue in between). Parsers from voyager 1 (lib/yenc,
lib/rar, lib/par2, lib/content sniff) with their tests; XoverClient.body;
yencode.

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

lib/nntp/xover_client.ts

@@ -34,6 +34,9 @@ const DOT_LINE = Buffer.from('.\r\n')
  * followed by a plain "." line; an empty range is a 420 without body.
  * About six times less traffic per header (LOG.md 2026-10-05).
  */
+/** The server doesn't have the article (430): taken down or expired. */
+export class MissingArticle extends Error {}
+
 export class XoverClient {
   private chunks: Buffer[] = []
   private length = 0
@@ -228,6 +231,37 @@ export class XoverClient {
     }
   }
 
+  /**
+   * An article's body by message-id, raw (dot-stuffed, "\r\n.\r\n" cut off):
+   * yEnc decoding undoes the stuffing. A connection without COMPRESS GZIP.
+   * 430 (no such article) throws MissingArticle.
+   */
+  async body(messageId: string): Promise<Buffer> {
+    return this.timed(async () => {
+      const id = messageId.startsWith('<') ? messageId : `<${messageId}>`
+      const reply = await this.command(`BODY ${id}`)
+      if (reply.startsWith('430') || reply.startsWith('423')) throw new MissingArticle(reply)
+      await this.expect(reply, ['222'])
+      return this.rawBody()
+    })
+  }
+
+  /** A multi-line body up to "\r\n.\r\n", as bytes, the terminator cut off. */
+  private async rawBody(): Promise<Buffer> {
+    let searched = 0
+    while (true) {
+      const all = this.buffer()
+      if (all.length >= 3 && searched === 0 && all.subarray(0, 3).equals(DOT_LINE)) {
+        this.take(3)
+        return Buffer.alloc(0)
+      }
+      const at = all.indexOf(TERMINATOR, Math.max(0, searched - TERMINATOR.length))
+      if (at !== -1) return Buffer.from(this.take(at + TERMINATOR.length).subarray(0, at + 2))
+      searched = all.length
+      await this.more()
+    }
+  }
+
   /** A plain multi-line body, up to "\r\n.\r\n", dot-unstuffed. */
   private async plainBody(): Promise<string> {
     let searched = 0