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

tests/test_routing.py

@@ -7,10 +7,10 @@ import frontmatter
 import httpx
 import pytest
 
-from beaver_gateway.core.auth import TokenStore
-from beaver_gateway.core.conversation_store import load_messages, rewrite_messages
-from beaver_gateway.core.gateway_tools import _tools
-from beaver_gateway.core.registry import McpRegistry
+from beaver_gateway.security.auth import TokenStore
+from beaver_gateway.frontends.markdown.history import load_messages, rewrite_messages
+from beaver_gateway.conversations.tools import _tools
+from beaver_gateway.app import McpRegistry
 from beaver_gateway.frontends.anthropic import AnthropicMessagesFrontend
 from beaver_gateway.frontends.api import ApiFrontend
 from beaver_gateway.frontends.base import GatewayRuntime
@@ -127,10 +127,10 @@ async def test_api_spawn_deep_lands_in_vault(stack: Stack) -> None:
         )
         assert r.status_code == 400
     path = stack.vault / rel
-    text = await stack.wait_file(path, "ok:[сид: brief]")
+    text = await stack.wait_file(path, "ok:[seed: brief]")
     post = frontmatter.loads(text)
     assert post.metadata == {"agent": "d", "conversation_id": body["id"]}
-    assert post.content.startswith("### User:\n\n[сид: brief] deep «Тема», ")
+    assert post.content.startswith("### User:\n\n[seed: brief] deep «Тема», ")
     assert post.content.rstrip().endswith("### User:")