The window worker keeps its window over a chunk that doesn't inflate

A live reply cut short (the server's compressed data ending at ".\r\n" at a
read boundary; the spool keeps what Corpus.write refuses) made the worker give
the group back without a snapshot, losing the window and the batch since its
last post (six times in the first 40 minutes on homelab). Now the batch before
the chunk goes out, the chunk is reported (fetched again, plain the second
time) and the range is asked for again from that chunk (RangeOutcome::Again):
the stream waits for the new copy and the window stays. Test: the coordinator
hands the same range back at its resume point after a corrupt report.

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

edge/README.md

@@ -256,7 +256,9 @@ COORDINATOR_URL=http://coordinator:3334 NODE_TOKEN=… ./target/release/edge-nod
   409 means the lease is lost (the range stops, isn't given back); a
   batch once 500k articles or 100k files wait (a picture group's batches
   went over the server's 256 MB limit); a chunk that doesn't inflate is
-  reported (the coordinator fetches it plain next time); SIGTERM/SIGINT
+  reported (the coordinator fetches it plain next time) after the batch
+  before it went out, and a held group asks for the range again from
+  that chunk, its window kept; SIGTERM/SIGINT
   give each range back after its current chunk; `--max-mbit` is the
   node's download cap, shared by its threads. Plus a heartbeat when no
   batch went out for a minute.