The par2 merge: releases whose files one par2 set describes become one

The prober stores, per probed article that starts a file, the MD5 of its
first 16 KiB (file_hashes), and per par2 body the set's whole file list
(par2_files, par2_sets): FileDesc holds the same hash per file, whatever
the file was renamed to. releases:merge (the merger service, no NNTP)
merges every minute the releases of one group, posted within 48 hours of
a release holding the set's par2, whose files the set describes, into the
one with the most files: chunks, probe candidates, inspections, hashes and
counts move; the par2's shared name when none was readable; release_merges
keeps what went where. Obfuscated uploads whose files were each a release
of their own ("[9/20] - "14f5999a…"", hep: 13,232) become one.

Also: corpus_sweep.py counts the marked ranges without psql's command tag.

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

deploy/compose.yaml

@@ -108,6 +108,12 @@ services:
       <<: *app-env
       PROBE_CONNECTIONS: ${PROBE_CONNECTIONS:-6}
 
+  # The par2 merge: releases whose files one par2 set describes (what the prober read) become one. No NNTP.
+  merger:
+    <<: *app
+    command: ['node', 'ace', 'releases:merge']
+    volumes: []
+
   # The Rust worker; it has no NNTP account and talks to node-api only.
   # Stopped before node-api (a worker holding a stream keeps the server from
   # exiting).