fix(client,exporter): handle HTTP 429 retry and sanitize JSON

_get_with_retry now retries on HTTP 429 responses, respecting the
Retry-After header when present. exporter sanitizes control characters
(0x00-0x1F except \n \r \t) in text fields before JSON serialization.

fixes #11
fixes #12

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_client.py

@@ -210,6 +210,83 @@ class TestGetWithRetry:
         mock_sleep.assert_any_call(2.0)
 
 
+class TestGetWithRetry429:
+    """Test _get_with_retry method (retry on HTTP 429 rate limiting)."""
+
+    def _make_client(self):
+        return GiteaClient("http://gitea.local:3000", "tok")
+
+    def _make_429_response(self, retry_after=None):
+        """Create a mock 429 response."""
+        resp = MagicMock()
+        resp.status_code = 429
+        resp.headers = {"Retry-After": retry_after} if retry_after is not None else {}
+        resp.raise_for_status.side_effect = requests.HTTPError(
+            "429 Too Many Requests", response=resp
+        )
+        return resp
+
+    def _make_200_response(self):
+        resp = MagicMock()
+        resp.status_code = 200
+        return resp
+
+    @patch("time.sleep")
+    def test_retry_on_429_with_retry_after(self, mock_sleep):
+        """429 with Retry-After header: sleeps for the indicated duration, then succeeds."""
+        client = self._make_client()
+        resp_429 = self._make_429_response(retry_after="2")
+        resp_200 = self._make_200_response()
+
+        with patch.object(client.session, "get", side_effect=[resp_429, resp_200]):
+            result = client._get_with_retry("http://gitea.local:3000/api/v1/test")
+
+        assert result.status_code == 200
+        mock_sleep.assert_called_once_with(2.0)
+
+    @patch("time.sleep")
+    def test_retry_on_429_without_retry_after(self, mock_sleep):
+        """429 without Retry-After header: uses linear backoff (1.0s for first retry)."""
+        client = self._make_client()
+        resp_429 = self._make_429_response()
+        resp_200 = self._make_200_response()
+
+        with patch.object(client.session, "get", side_effect=[resp_429, resp_200]):
+            result = client._get_with_retry("http://gitea.local:3000/api/v1/test")
+
+        assert result.status_code == 200
+        mock_sleep.assert_called_once_with(1.0)
+
+    @patch("time.sleep")
+    def test_retry_on_429_exhausted(self, mock_sleep):
+        """3 consecutive 429 responses: raises HTTPError after exhausting retries."""
+        client = self._make_client()
+        resp_429 = self._make_429_response()
+
+        with patch.object(client.session, "get", return_value=resp_429):
+            with pytest.raises(requests.HTTPError):
+                client._get_with_retry("http://gitea.local:3000/api/v1/test")
+
+        assert mock_sleep.call_count == 2
+
+    @patch("time.sleep")
+    def test_retry_on_429_then_timeout(self, mock_sleep):
+        """429 followed by Timeout: both retry types handled in same loop."""
+        client = self._make_client()
+        resp_429 = self._make_429_response()
+        resp_200 = self._make_200_response()
+
+        with patch.object(
+            client.session,
+            "get",
+            side_effect=[resp_429, requests.Timeout("timeout"), resp_200],
+        ):
+            result = client._get_with_retry("http://gitea.local:3000/api/v1/test")
+
+        assert result.status_code == 200
+        assert mock_sleep.call_count == 2
+
+
 class TestGetLatestCommit:
     """Test get_latest_commit method."""