Posting-time windows into the corpus: ranges:dates, ranges:capture

ranges:dates samples each active group's posting dates from the news
server (group_dates) and estimates every range's date (ranges.est_date).
ranges:capture --from --to marks a window's ranges of every group for the
corpus. The corpus fill takes capture ranges in priority order, done ones
too, and remembers complete ones (ranges.stored_at).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

database/migrations/1770000004900_range_dates.ts

@@ -0,0 +1,27 @@
+import { BaseSchema } from '@adonisjs/lucid/schema'
+
+/**
+ * When a group's articles were posted, sampled from the news server (ranges:dates; app/services/group_dates.ts), and
+ * from those each range's estimated posting date, so ranges can be chosen by era: ranges:capture --from --to marks a
+ * posting-time window of every group for the corpus (voyager 3's test data; REBUILD.md, corpus). `stored_at`: the
+ * range is complete in the corpus (the prefetcher saw its range.json), so the corpus fill skips it without looking.
+ */
+export default class extends BaseSchema {
+  async up() {
+    this.schema.raw(`
+      CREATE TABLE IF NOT EXISTS group_dates (
+        group_id integer NOT NULL REFERENCES groups (id) ON DELETE CASCADE,
+        article bigint NOT NULL,
+        posted_at timestamptz NOT NULL,
+        PRIMARY KEY (group_id, article)
+      )`)
+    this.schema.raw(`ALTER TABLE ranges ADD COLUMN IF NOT EXISTS est_date timestamptz`)
+    this.schema.raw(`ALTER TABLE ranges ADD COLUMN IF NOT EXISTS stored_at timestamptz`)
+  }
+
+  async down() {
+    this.schema.raw(`ALTER TABLE ranges DROP COLUMN IF EXISTS stored_at`)
+    this.schema.raw(`ALTER TABLE ranges DROP COLUMN IF EXISTS est_date`)
+    this.schema.raw(`DROP TABLE IF EXISTS group_dates`)
+  }
+}