feat: add extension_paths parameter for loading Chrome extensions (#210)

Add `extension_paths` parameter to all launch functions (Python + JS) for loading Chrome extensions.

Resolves paths to absolute, injects `--load-extension` and `--disable-extensions-except` flags via `build_args()`.

Note: Extensions require a persistent context (`launch_persistent_context`) to function — this is a Chromium limitation.

Co-authored-by: zackycodes <75211659+zackycodes@users.noreply.github.com>

tests/test_extension_loading.py

@@ -0,0 +1,33 @@
+import os
+from unittest.mock import MagicMock, patch
+
+from cloakbrowser import launch
+
+
+@patch("cloakbrowser.browser.ensure_binary")
+@patch("cloakbrowser.browser._import_sync_playwright")
+def test_extension_loading(mock_playwright_import, mock_ensure_binary):
+    mock_ensure_binary.return_value = "/fake/chrome"
+
+    mock_browser = MagicMock()
+
+    mock_pw = MagicMock()
+    mock_pw.chromium.launch.return_value = mock_browser
+
+    mock_pw_manager = MagicMock()
+    mock_pw_manager.return_value.start.return_value = mock_pw
+
+    mock_playwright_import.return_value = mock_pw_manager
+
+    launch(extension_paths=["./ext"])
+
+    mock_pw.chromium.launch.assert_called_once()
+
+    launch_call = mock_pw.chromium.launch.call_args
+
+    args = launch_call.kwargs["args"]
+
+    abs_path = os.path.abspath("./ext")
+
+    assert f"--load-extension={abs_path}" in args
+    assert f"--disable-extensions-except={abs_path}" in args