refactor: update internal helpers and improve slugify function usage

backend/app/services/openclaw/internal/__init__.py

@@ -1,6 +1,7 @@
-"""Internal typed helpers shared across OpenClaw service modules."""
+"""Internal typed helpers shared across OpenClaw service modules.
 
-from .agent_key import agent_key
-from .retry import with_coordination_gateway_retry
+Import submodules directly (for example: ``app.services.openclaw.internal.agent_key``)
+to avoid shadowing submodule names with re-exported symbols.
+"""
 
-__all__ = ["agent_key", "with_coordination_gateway_retry"]
+__all__: list[str] = []