nisse-review: one unlistable repository holds up no other

Found at bring-up: an empty private repository's /pulls answered 404, and
intake stopped there, so the whole round failed and nothing was reviewed.
A repository whose PRs can't be listed is now logged (intake.repo_failed)
and skipped for the round; its items stay as they are.

Also, from nisse-review's review of this PR: a two-page test pins the
search listing the patterns rest on.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-review/tests/test_review.py

@@ -328,6 +328,20 @@ def test_patterns_reach_public_repositories_the_account_was_not_given(
     assert w["store"].work_item("infra/tofu#3") is None
 
 
+def test_a_repository_whose_prs_cannot_be_listed_holds_up_no_other(
+    tmp_path: Path,
+) -> None:
+    # Found at bring-up: an empty private repository's /pulls was a 404,
+    # and the round stopped there, so no repository was reviewed.
+    gitea = FakeGitea(repos={"a/empty": [], REPO: [pr()]}, unlisted={"a/empty"})
+    out = io.StringIO()
+    w = world(tmp_path, Scripted(*REVIEW), gitea)
+    w["scheduler"]._oplog = OpLog("t", out)
+    assert w["scheduler"].round() is True  # REPO's PR was reviewed
+    assert item(w).position == REVIEWED
+    assert '"intake.repo_failed"' in out.getvalue() and "a/empty" in out.getvalue()
+
+
 def test_a_configured_repository_it_cannot_read_is_left_out() -> None:
     gitea = FakeGitea(repos={REPO: []})
     out = io.StringIO()