Fold sidecars (.nfo, .sfv, .nzb) apart from their upload into it

"Murdoch Mysteries S8D1 [00/80] - \"….nzb\"" beside its "[01/94]" upload
was a release of its own (23k sidecar-only releases on the corpus, 15k with
the poster's bigger release within 10 minutes). The settler queues small
settled releases (fold_candidates); the merger's third pass folds one whose
files are all sidecars into the poster's bigger release in the same group
within 10 minutes: the one sharing a 4+ letter word with its subject, else
the one under the same counter total, else none (via 'sidecar').

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

database/migrations/1770000003400_fold_candidates.ts

@@ -0,0 +1,20 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * Small releases the settler just settled (at most 3 files, under 1 MB), queued for the merger's sidecar fold
+ * (app/services/sidecar_folder.ts): an .nfo, .sfv or .nzb that came apart from its upload (another counter, another
+ * name) joins it. A queue, so the fold needn't scan the releases (LOG.md 2026-10-15 (57)).
+ */
+export default class extends BaseSchema {
+  async up() {
+    this.schema.raw(`
+      CREATE TABLE fold_candidates (
+        release_id bigint PRIMARY KEY,
+        created_at timestamptz NOT NULL DEFAULT now()
+      )`)
+  }
+
+  async down() {
+    this.schema.raw(`DROP TABLE IF EXISTS fold_candidates`)
+  }
+}