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

src/beaver_gateway/core/registry.py

@@ -16,6 +16,7 @@ if TYPE_CHECKING:
     from collections.abc import Iterable, Iterator
 
     from beaver_gateway.agents.base import BaseAgent
+    from beaver_gateway.core.conversations import ConversationTexts
     from beaver_gateway.frontends.base import Frontend
     from beaver_gateway.mcp.types import McpServerT
 
@@ -81,3 +82,5 @@ class Gateway:
     agents: list[BaseAgent] = field(default_factory=list)
     mcps: list[McpServerT] = field(default_factory=list)
     frontends: list[Frontend] = field(default_factory=list)
+    texts: ConversationTexts | None = None
+    """Merge prompt and seed bodies for ``core/conversations`` (§8.2-8.3)."""