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

tests/test_mcp_redacting.py

@@ -5,8 +5,8 @@ import pytest
 from fastmcp import FastMCP
 from fastmcp.tools.base import ToolResult
 
-from beaver_gateway.core import redact as redact_mod
-from beaver_gateway.core.redact import redact
+from beaver_gateway.security import redact as redact_mod
+from beaver_gateway.security.redact import redact
 from beaver_gateway.mcp.internal_app import build_internal_app
 from beaver_gateway.mcp.redacting import RedactingMiddleware
 from beaver_gateway.mcp.types import McpServer
@@ -179,7 +179,7 @@ async def test_gateway_own_tools_are_filtered_too() -> None:
     # in-process — so they carry their own wrapper.
     from claude_agent_sdk import SdkMcpTool
 
-    from beaver_gateway.core.gateway_tools import _redacting
+    from beaver_gateway.conversations.tools import _redacting
 
     async def handler(_args: dict[str, object]) -> dict[str, object]:
         return {"content": [{"type": "text", "text": KOMODO_DEPLOY}]}