feat(policy,claude_sdk,cli,config_loader): pretooluse policy rules per agent, tool call audit, sibling imports for config

src/beaver_gateway/agents/claude.py

@@ -16,6 +16,7 @@ from pydantic import BaseModel, ConfigDict, Field, model_validator
 
 from beaver_gateway.agents.base import BaseAgent
 from beaver_gateway.core.kinds import KINDS, Kind
+from beaver_gateway.core.policy import PolicyRule  # noqa: TC001 - pydantic runtime
 from beaver_gateway.core.prompt import PromptSource  # noqa: TC001 - pydantic runtime
 
 __all__ = ["ClaudeAgent", "ClaudeOptions", "Prompts"]
@@ -86,6 +87,9 @@ class ClaudeAgent(BaseAgent):
     ``say``, ``schedule``, ``inject``); empty = no gateway MCP server."""
 
     options: ClaudeOptions = Field(default_factory=ClaudeOptions)
+    policy: tuple[PolicyRule, ...] = ()
+    """``PreToolUse`` rules (§3.7), run in order on every tool call; the
+    first ``Deny`` is what the model reads back. See ``core/policy``."""
 
     @model_validator(mode="after")
     def _kinds_follow_prompts(self) -> ClaudeAgent: