feat: move binary releases to wrapper repo, add auto-update check

- Binary downloads now served from CloakHQ/cloakbrowser releases (chromium-v* tags)
- Auto-update: background version check on launch, downloads newer binary for next use
- Graceful error on macOS/Windows (Linux-only binaries for now)
- Rate-limited (1hr), opt-out via CLOAKBROWSER_AUTO_UPDATE=false
- Add release-binary.yml workflow for anonymous binary releases

tests/test_update.py

@@ -0,0 +1,172 @@
+"""Tests for auto-update and version management."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from cloakbrowser.config import (
+    CHROMIUM_VERSION,
+    _version_newer,
+    _version_tuple,
+    get_download_url,
+    get_effective_version,
+)
+from cloakbrowser.download import (
+    _get_latest_chromium_version,
+    _should_check_for_update,
+)
+
+
+class TestVersionComparison:
+    def test_version_tuple_parsing(self):
+        assert _version_tuple("145.0.7718.0") == (145, 0, 7718, 0)
+        assert _version_tuple("142.0.7444.175") == (142, 0, 7444, 175)
+
+    def test_newer_version(self):
+        assert _version_newer("145.0.7718.0", "142.0.7444.175") is True
+
+    def test_older_version(self):
+        assert _version_newer("142.0.7444.175", "145.0.7718.0") is False
+
+    def test_same_version(self):
+        assert _version_newer("142.0.7444.175", "142.0.7444.175") is False
+
+    def test_patch_bump(self):
+        assert _version_newer("142.0.7444.176", "142.0.7444.175") is True
+
+    def test_major_bump(self):
+        assert _version_newer("143.0.0.0", "142.9.9999.999") is True
+
+
+class TestDownloadUrl:
+    def test_default_url_format(self):
+        url = get_download_url()
+        assert "github.com/CloakHQ/cloakbrowser/releases/download" in url
+        assert f"chromium-v{CHROMIUM_VERSION}" in url
+        assert url.endswith(".tar.gz")
+
+    def test_custom_version_url(self):
+        url = get_download_url("145.0.7718.0")
+        assert "chromium-v145.0.7718.0" in url
+
+    def test_no_old_repo_reference(self):
+        url = get_download_url()
+        assert "chromium-stealth-builds" not in url
+
+
+class TestShouldCheckForUpdate:
+    def test_disabled_by_env(self):
+        with patch.dict(os.environ, {"CLOAKBROWSER_AUTO_UPDATE": "false"}):
+            assert _should_check_for_update() is False
+
+    def test_disabled_by_env_case_insensitive(self):
+        with patch.dict(os.environ, {"CLOAKBROWSER_AUTO_UPDATE": "False"}):
+            assert _should_check_for_update() is False
+
+    def test_disabled_by_binary_override(self):
+        with patch.dict(os.environ, {"CLOAKBROWSER_BINARY_PATH": "/some/path"}):
+            assert _should_check_for_update() is False
+
+    def test_disabled_by_custom_download_url(self):
+        with patch.dict(
+            os.environ, {"CLOAKBROWSER_DOWNLOAD_URL": "https://my-mirror.com"}
+        ):
+            assert _should_check_for_update() is False
+
+    def test_rate_limited(self, tmp_path):
+        import time
+
+        with patch.dict(
+            os.environ,
+            {
+                "CLOAKBROWSER_CACHE_DIR": str(tmp_path),
+                "CLOAKBROWSER_BINARY_PATH": "",
+                "CLOAKBROWSER_AUTO_UPDATE": "",
+                "CLOAKBROWSER_DOWNLOAD_URL": "",
+            },
+        ):
+            check_file = tmp_path / ".last_update_check"
+            check_file.write_text(str(time.time()))
+            assert _should_check_for_update() is False
+
+    def test_stale_rate_limit_allows_check(self, tmp_path):
+        import time
+
+        with patch.dict(
+            os.environ,
+            {
+                "CLOAKBROWSER_CACHE_DIR": str(tmp_path),
+                "CLOAKBROWSER_BINARY_PATH": "",
+                "CLOAKBROWSER_AUTO_UPDATE": "",
+                "CLOAKBROWSER_DOWNLOAD_URL": "",
+            },
+        ):
+            check_file = tmp_path / ".last_update_check"
+            check_file.write_text(str(time.time() - 7200))  # 2 hours ago
+            assert _should_check_for_update() is True
+
+
+class TestEffectiveVersion:
+    def test_no_marker_returns_hardcoded(self, tmp_path):
+        with patch.dict(os.environ, {"CLOAKBROWSER_CACHE_DIR": str(tmp_path)}):
+            assert get_effective_version() == CHROMIUM_VERSION
+
+    def test_marker_with_newer_version(self, tmp_path):
+        with patch.dict(os.environ, {"CLOAKBROWSER_CACHE_DIR": str(tmp_path)}):
+            marker = tmp_path / "latest_version"
+            marker.write_text("999.0.0.0")
+            # Binary doesn't exist, so should fall back
+            assert get_effective_version() == CHROMIUM_VERSION
+
+    def test_marker_with_older_version_ignored(self, tmp_path):
+        with patch.dict(os.environ, {"CLOAKBROWSER_CACHE_DIR": str(tmp_path)}):
+            marker = tmp_path / "latest_version"
+            marker.write_text("100.0.0.0")
+            assert get_effective_version() == CHROMIUM_VERSION
+
+
+class TestGetLatestVersion:
+    def test_parses_chromium_tag(self):
+        mock_response = MagicMock()
+        mock_response.json.return_value = [
+            {"tag_name": "chromium-v145.0.7718.0", "draft": False},
+            {"tag_name": "chromium-v142.0.7444.175", "draft": False},
+        ]
+        mock_response.raise_for_status = MagicMock()
+
+        with patch("cloakbrowser.download.httpx.get", return_value=mock_response):
+            result = _get_latest_chromium_version()
+            assert result == "145.0.7718.0"
+
+    def test_skips_draft_releases(self):
+        mock_response = MagicMock()
+        mock_response.json.return_value = [
+            {"tag_name": "chromium-v999.0.0.0", "draft": True},
+            {"tag_name": "chromium-v145.0.7718.0", "draft": False},
+        ]
+        mock_response.raise_for_status = MagicMock()
+
+        with patch("cloakbrowser.download.httpx.get", return_value=mock_response):
+            result = _get_latest_chromium_version()
+            assert result == "145.0.7718.0"
+
+    def test_skips_non_chromium_tags(self):
+        mock_response = MagicMock()
+        mock_response.json.return_value = [
+            {"tag_name": "v0.2.0", "draft": False},
+            {"tag_name": "chromium-v145.0.7718.0", "draft": False},
+        ]
+        mock_response.raise_for_status = MagicMock()
+
+        with patch("cloakbrowser.download.httpx.get", return_value=mock_response):
+            result = _get_latest_chromium_version()
+            assert result == "145.0.7718.0"
+
+    def test_network_error_returns_none(self):
+        with patch("cloakbrowser.download.httpx.get", side_effect=Exception("timeout")):
+            result = _get_latest_chromium_version()
+            assert result is None