test(pins): whitelist download_queue_pos on raw media rows (additive widening)

The contract pin caught the §0 item 4 column surfacing on media-list
raw sqlc rows — its job. Widened additively per doctrine: rawRowKeys +
docs/contract_pins.md changelog entry. NULL for scan rows and
never-queued episodes; nothing removed or renamed.

cmd/server/tests/contract_pins_test.go

@@ -761,6 +761,10 @@ func TestContractPin_MediaListBothBranches(t *testing.T) {
 		"declared_duration_seconds", "transcript_url", "chapters_url",
 		"hosts", "guests", "download_state", "download_error",
 		"download_attempts",
+		// §0 item 4 (2026-10-30 additive widening): the download pool's
+		// queue ticket — SEQUENCE-stamped at enqueue, NULL for scan rows
+		// and never-queued episodes. See docs/contract_pins.md changelog.
+		"download_queue_pos",
 	}
 	resolvedKeys := []string{
 		"id", "library_id", "title", "subtitle", "author", "authors", "isbn", "description",