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/capability_apply.py

@@ -36,7 +36,7 @@ from pathlib import Path
 
 from ...agent_provider import get_provider
 from ...log import info, warn
-from .bottle_state import (
+from ...bottle_state import (
     mark_preserved,
     per_bottle_dockerfile,
     transcript_snapshot_dir,