fix(plugins): late-binding subagent runtime for non-gateway load paths (#46648)

Merged via squash.

Prepared head SHA: 44742652c9
Co-authored-by: jalehman <550978+jalehman@users.noreply.github.com>
Co-authored-by: jalehman <550978+jalehman@users.noreply.github.com>
Reviewed-by: @jalehman

src/agents/runtime-plugins.ts

@@ -5,6 +5,7 @@ import { resolveUserPath } from "../utils.js";
 export function ensureRuntimePluginsLoaded(params: {
   config?: OpenClawConfig;
   workspaceDir?: string | null;
+  allowGatewaySubagentBinding?: boolean;
 }): void {
   const workspaceDir =
     typeof params.workspaceDir === "string" && params.workspaceDir.trim()
@@ -14,5 +15,10 @@ export function ensureRuntimePluginsLoaded(params: {
   loadOpenClawPlugins({
     config: params.config,
     workspaceDir,
+    runtimeOptions: params.allowGatewaySubagentBinding
+      ? {
+          allowGatewaySubagentBinding: true,
+        }
+      : undefined,
   });
 }