fix: a test restore has its own stall threshold, and the dumps list test knows its new fields

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_api_system_backup.py

@@ -528,10 +528,13 @@ async def test_the_bucket_dumps_are_listed_with_their_confirmation(
     ])
     resp = await client.get("/api/system/backup/offsite/dumps")
     assert resp.status_code == 200
-    assert (await resp.get_json())["dumps"] == [{
+    body = await resp.get_json()
+    assert body["dumps"] == [{
         "key": _DUMP, "ts": "20261107T134258Z", "size_bytes": 3222868924,
-        "confirm": "restore-offsite-20261107T134258Z",
+        "counted": False, "confirm": "restore-offsite-20261107T134258Z",
     }]
+    # What a test restore needs free on the database's disk.
+    assert body["database_bytes"] > 0
 
 
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