feat(webapp-access): add WEBAPP_PUBLIC_ACCESS_ENABLED toggle (#38567)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/tests/unit_tests/services/test_feature_service_webapp_public_access.py

@@ -0,0 +1,30 @@
+import pytest
+
+from services.feature_service import FeatureService, SystemFeatureModel
+
+
+@pytest.mark.parametrize(
+    ("env_value", "expected"),
+    [
+        (False, False),
+        (True, True),
+    ],
+    ids=["disabled_by_env", "enabled_by_env"],
+)
+def test_fulfill_system_params_from_env_sets_allow_public_access(
+    monkeypatch: pytest.MonkeyPatch,
+    env_value: bool,
+    expected: bool,
+):
+    monkeypatch.setattr("services.feature_service.dify_config.WEBAPP_PUBLIC_ACCESS_ENABLED", env_value)
+
+    system_features = SystemFeatureModel()
+    FeatureService._fulfill_system_params_from_env(system_features)
+
+    assert system_features.webapp_auth.allow_public_access is expected
+
+
+def test_get_system_features_defaults_allow_public_access_to_true():
+    system_features = FeatureService.get_system_features()
+
+    assert system_features.webapp_auth.allow_public_access is True