refactor: move bottle_state.py to top-level bot_bottle package

Both docker and smolmachines backends use bottle state helpers.
Moving to bot_bottle/ makes the sharing explicit and removes the
cross-backend dependency (smolmachines importing from ..docker).

All callers updated: docker backend, smolmachines backend, cli
modules, and tests.

bot_bottle/backend/docker/cleanup.py

@@ -31,7 +31,7 @@ from ... import supervise as _supervise
 from ...log import info, warn
 from . import util as docker_mod
 from .bottle_cleanup_plan import DockerBottleCleanupPlan
-from .bottle_state import bottle_state_dir, is_preserved
+from ...bottle_state import bottle_state_dir, is_preserved
 from .compose import COMPOSE_PROJECT_PREFIX, list_compose_projects