feat(memory): add hybrid gateway configuration

app-instance/backend/beaver/foundation/config/schema.py

@@ -115,6 +115,33 @@ class BackendIdentityConfig:
     public_base_url: str = ""
 
 
+@dataclass(slots=True)
+class MemoryGatewayConfig:
+    """Fixed Memory Gateway settings for one Beaver instance."""
+
+    base_url: str = ""
+    user_id: str = ""
+    user_key: str = field(default="", repr=False)
+    app_id: str = "default"
+    project_id: str = "default"
+    scope: list[str] = field(default_factory=lambda: ["current_chat", "resources"])
+    top_k: int = 8
+    timeout_seconds: float = 10.0
+
+    @property
+    def is_configured(self) -> bool:
+        return bool(_clean(self.base_url) and _clean(self.user_id) and _clean(self.user_key))
+
+
+@dataclass(slots=True)
+class MemoryConfig:
+    """Curated baseline plus optional Memory Gateway layer."""
+
+    mode: str = "hybrid"
+    explicit: bool = False
+    gateway: MemoryGatewayConfig = field(default_factory=MemoryGatewayConfig)
+
+
 @dataclass(slots=True)
 class BeaverConfig:
     """Config loaded once per backend sandbox instance."""
@@ -126,6 +153,7 @@ class BeaverConfig:
     authz: AuthzConfig = field(default_factory=AuthzConfig)
     channels: dict[str, ChannelConfig] = field(default_factory=dict)
     backend_identity: BackendIdentityConfig = field(default_factory=BackendIdentityConfig)
+    memory: MemoryConfig = field(default_factory=MemoryConfig)
     config_path: Path | None = None
 
     @property