An "ancient" range a group: articles 1 … low watermark − 1, never filled

Every group is tiled from article 1 now: one range with status 'ancient'
covers what had expired on the server before the group was planned.
Nothing selects it (leases, prefetcher, corpus fill, tail merger all take
'planned'), the status panel reports it apart, the search's history stats
leave it out. Migration 6700 adds it for the groups planned before;
Planner.historyRows (now a pure function, unit-tested) for new groups.
The status bands are ordered by an explicit key: the ancient row at
priority 0 tied "history 0-999" with "window 0".

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

app/services/search_service.ts

@@ -304,9 +304,9 @@ class SearchService {
     // History by articles; the pass: the history ranges before those deferred behind them (priority
     // 2000 apart; e.g. groups added later that go first).
     const { rows: ranges } = await db.rawQuery(
-      `WITH h AS (SELECT status, priority, end_id - start_id + 1 AS n FROM ranges WHERE priority >= 0),
+      `WITH h AS (SELECT status, priority, end_id - start_id + 1 AS n FROM ranges WHERE priority >= 0 AND status <> 'ancient'),
             pass AS (SELECT (floor(coalesce(min(priority) FILTER (WHERE status <> 'done'), 0) / 2000) + 1) * 2000 AS below FROM h)
-       SELECT (SELECT count(*) FILTER (WHERE status = 'done') FROM ranges) AS done, (SELECT count(*) FROM ranges) AS total,
+       SELECT (SELECT count(*) FILTER (WHERE status = 'done') FROM ranges) AS done, (SELECT count(*) FROM ranges WHERE status <> 'ancient') AS total,
               coalesce(sum(n) FILTER (WHERE status = 'done'), 0) AS history_done, coalesce(sum(n), 0) AS history,
               coalesce(sum(n) FILTER (WHERE status = 'done' AND priority < (SELECT below FROM pass)), 0) AS pass_done,
               coalesce(sum(n) FILTER (WHERE priority < (SELECT below FROM pass)), 0) AS pass,