feat(core,backends,frontends,storage): conversations, inject queue, session pool, gateway mcp tools, api frontend

src/beaver_gateway/frontends/base.py

@@ -12,7 +12,7 @@ from __future__ import annotations
 
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from collections.abc import Awaitable, Callable, Mapping, Sequence
@@ -77,6 +77,12 @@ class GatewayRuntime:
     # to keep ``anthropic.types`` out of the runtime import graph for
     # this base module.
     turn_log_handlers: list[TurnLogHandler] = field(default_factory=list)
+    # M1b: conversations service, event bus and the shared session pool.
+    # ``Any`` for the same import-graph reason as above; ``None`` only in
+    # tests that build a runtime without them.
+    conversations: Any = None
+    bus: Any = None
+    pool: Any = None
 
 
 class Frontend(ABC):