fix(web): two api_v3 paths called names that no longer exist (#625)

The Pixlet editor stop route restarts the display after a SIGKILL with
_run_systemctl_command, which starlark.py never imported (since #554). The
Starlark device-location resolver fell back to _ensure_cache_manager, which
#609 deleted; the resolver already accepts no cache manager. Both raised
NameError on the rare path that reaches them. pyflakes finds no other
undefined names in src/ or web_interface/.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

test/web_interface/test_api_v3_names_resolve.py

@@ -0,0 +1,25 @@
+"""Names two rarely-run api_v3 paths call must exist.
+
+Both slipped through because nothing exercised them: the Pixlet editor's
+stop route only restarts the display after a SIGKILL, and the Starlark
+device-location resolver only builds a cache manager when the web app has
+not set one. Either raised NameError when it finally ran.
+"""
+
+from unittest.mock import patch
+
+from test._api_v3_test_helpers import api_v3_module  # noqa: F401
+
+
+def test_the_editor_stop_route_can_restart_the_display():
+    from web_interface.blueprints.api_v3 import starlark
+
+    assert callable(starlark._run_systemctl_command)
+
+
+def test_the_device_location_resolver_builds_without_a_cache_manager(api_v3_module):
+    pkg = api_v3_module
+    with patch.object(pkg.api_v3, 'cache_manager', None, create=True), \
+            patch.object(pkg, '_starlark_device_location', None):
+        resolver = pkg._get_starlark_device_location()
+    assert resolver.cache_manager is None

web_interface/blueprints/api_v3/__init__.py

@@ -1712,7 +1712,7 @@ def _get_starlark_device_location() -> DeviceLocationResolver:
     global _starlark_device_location
     if _starlark_device_location is None:
         _starlark_device_location = DeviceLocationResolver(
-            getattr(api_v3, 'cache_manager', None) or _ensure_cache_manager(), logger)
+            getattr(api_v3, 'cache_manager', None), logger)
     return _starlark_device_location
 
 

web_interface/blueprints/api_v3/starlark.py

@@ -11,6 +11,7 @@ from web_interface.blueprints.api_v3 import (
     _PIXLET_EDITOR_DEFAULT_TIMEOUT, _PIXLET_EDITOR_MAX_TIMEOUT,
     _PIXLET_EDITOR_SCRIPT, _PIXLET_EDITOR_STATE, _clear_pixlet_editor_state,
     _find_pixlet_binary, _install_star_file, _pixlet_editor_alive,
+    _run_systemctl_command,
     _pixlet_editor_status, _read_pixlet_editor_state,
     _STARLARK_APPS_DIR, _standalone_render_starlark_app,
     _starlark_github_token, _starlark_manifest_lock,