edge-bench --group: a range after a gap starts its batch at the range

a.b.storage's stored 2016 ranges are not contiguous (its 2016 window lies in two
article regions); the batch after a gap kept the previous range's end as its
start and the harness found no leased range for it.

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

edge/src/indexer.rs

@@ -937,6 +937,15 @@ impl RangeIndexer {
         self.batch.next = self.end + 1;
     }
 
+    /// The next range of a group starts after a gap (edge-bench --group, the corpus holding some ranges only): a fresh
+    /// batch starts there, not at the previous range's end; the window carries on. Nothing when the batch has anything.
+    pub fn skip_to(&mut self, article: i64) {
+        if self.batch.headers == 0 && self.batch.releases.is_empty() && self.batch.candidates.is_empty() && self.batch.from < article {
+            self.batch.from = article;
+            self.batch.next = article;
+        }
+    }
+
     /// Files in the releases finished since the last take (RangeIndexer.pending).
     pub fn pending(&self) -> usize {
         self.pending_files