Fix package dependency direction (#2859)

Move `LOCAL_BACKEND_ENABLED` from
`dstack._internal.server.settings` to
`dstack._internal.settings`, so that it can be
imported to both `dstack._internal.server` and
`dstack._internal.core`.

Author: jvstme

src/dstack/_internal/core/backends/__init__.py

@@ -11,7 +11,7 @@
 from dstack._internal.core.backends.configurators import list_available_configurator_classes
 from dstack._internal.core.backends.local.compute import LocalCompute
 from dstack._internal.core.models.backends.base import BackendType
-from dstack._internal.server.settings import LOCAL_BACKEND_ENABLED
+from dstack._internal.settings import LOCAL_BACKEND_ENABLED
 
 
 def _get_backends_with_compute_feature(

src/dstack/_internal/server/services/backends/__init__.py

@@ -35,7 +35,7 @@
 from dstack._internal.core.models.runs import Requirements
 from dstack._internal.server import settings
 from dstack._internal.server.models import BackendModel, DecryptedString, ProjectModel
-from dstack._internal.server.settings import LOCAL_BACKEND_ENABLED
+from dstack._internal.settings import LOCAL_BACKEND_ENABLED
 from dstack._internal.utils.common import run_async
 from dstack._internal.utils.logging import get_logger
 

src/dstack/_internal/server/settings.py

@@ -97,8 +97,6 @@
 
 SQL_ECHO_ENABLED = os.getenv("DSTACK_SQL_ECHO_ENABLED") is not None
 
-LOCAL_BACKEND_ENABLED = os.getenv("DSTACK_LOCAL_BACKEND_ENABLED") is not None
-
 UPDATE_DEFAULT_PROJECT = os.getenv("DSTACK_UPDATE_DEFAULT_PROJECT") is not None
 DO_NOT_UPDATE_DEFAULT_PROJECT = os.getenv("DSTACK_DO_NOT_UPDATE_DEFAULT_PROJECT") is not None
 SKIP_GATEWAY_UPDATE = os.getenv("DSTACK_SKIP_GATEWAY_UPDATE", None) is not None

src/dstack/_internal/settings.py

@@ -19,6 +19,10 @@
 )
 DSTACK_DIND_IMAGE = os.getenv("DSTACK_DIND_IMAGE", "dstackai/dind")
 
+# Development settings
+
+LOCAL_BACKEND_ENABLED = os.getenv("DSTACK_LOCAL_BACKEND_ENABLED") is not None
+
 
 class FeatureFlags:
     """