Probe 7z listings and ZIP starts

7z keeps its file list at the end of the archive, so the 7z-tail
candidates (the last segment of the highest volume) were queued but
never probed, and the .7z.001 start only gave the type. The prober now
claims 7z-tail candidates after the archives; lib/sevenzip finds the end
header in the article, decodes the LZMA-packed header (a TypeScript port
of the LZMA SDK's reference decoder) and lists the files with their
sizes. An AES-encrypted header means passworded without names. Names
feed the inner name and the judge's fake rule.

An unsplit .7z of several segments now also gets a tail candidate, and
.zip files an archive candidate: their first segment's local headers
give the first entries and whether they are encrypted. Both in the Rust
edge and the TypeScript indexer.

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

lib/edge/range_indexer.ts

@@ -434,6 +434,8 @@ export function candidatesOf(key: string, files: AggregatedFile<EdgeSegment>[],
       if (!tail || volume > tail.volume) tail = { volume, file: f }
       continue
     }
+    // An unsplit 7z of more than one segment: its listing is in its last one.
+    if (volume === 0 && f.segments.length > 1 && !tail) tail = { volume, file: f }
     if (isArchiveStart(name)) out.push({ releaseKey: key, upload, kind: 'archive', messageId: f.segments[0].messageId, file: name })
     else if (/\.par2$/i.test(name) && !isLaterVolume(name)) out.push({ releaseKey: key, upload, kind: 'par2', messageId: f.segments[0].messageId, file: name })
   }