refactor: split flat core into capability packages, layer the conversations service, English defaults for every model-facing text

src/beaver_gateway/mcp/redacting.py

@@ -20,7 +20,7 @@ remembering to list it here.
 What this does not reach: tools that never touch a FastMCP server — the
 gateway's own ``gateway`` tools, and everything claude-code runs inside
 its own process (``Bash``, ``Read``). Those are guarded by
-:mod:`beaver_gateway.core.policy` and the vault mounts instead.
+:mod:`beaver_gateway.agents.policy` and the vault mounts instead.
 """
 
 from __future__ import annotations
@@ -31,7 +31,7 @@ import mcp.types as mt
 from fastmcp.server.middleware import Middleware
 from fastmcp.tools.base import ToolResult
 
-from beaver_gateway.core.redact import redact, redact_data
+from beaver_gateway.security.redact import redact, redact_data
 
 if TYPE_CHECKING:
     from fastmcp.server.middleware import CallNext, MiddlewareContext