fix: preserve gateway-bindable loader compatibility

src/plugins/loader.runtime-registry.test.ts

@@ -18,6 +18,7 @@ import {
 } from "./memory-state.js";
 import { createEmptyPluginRegistry } from "./registry.js";
 import { setActivePluginRegistry } from "./runtime.js";
+import type { CreatePluginRuntimeOptions } from "./runtime/index.js";
 
 afterEach(() => {
   resetPluginLoaderTestStateForTest();
@@ -39,7 +40,7 @@ describe("getCompatibleActivePluginRegistry", () => {
       },
     };
     const { cacheKey } = __testing.resolvePluginLoadCacheContext(loadOptions);
-    setActivePluginRegistry(registry, cacheKey);
+    setActivePluginRegistry(registry, cacheKey, "gateway-bindable");
 
     expect(__testing.getCompatibleActivePluginRegistry(loadOptions)).toBe(registry);
     expect(
@@ -59,6 +60,38 @@ describe("getCompatibleActivePluginRegistry", () => {
         ...loadOptions,
         runtimeOptions: undefined,
       }),
+    ).toBe(registry);
+    expect(
+      __testing.getCompatibleActivePluginRegistry({
+        ...loadOptions,
+        runtimeOptions: {
+          subagent: {} as CreatePluginRuntimeOptions["subagent"],
+        },
+      }),
+    ).toBeUndefined();
+  });
+
+  it("does not treat a default-mode active registry as compatible with gateway binding", () => {
+    const registry = createEmptyPluginRegistry();
+    const loadOptions = {
+      config: {
+        plugins: {
+          allow: ["demo"],
+          load: { paths: ["/tmp/demo.js"] },
+        },
+      },
+      workspaceDir: "/tmp/workspace-a",
+    };
+    const { cacheKey } = __testing.resolvePluginLoadCacheContext(loadOptions);
+    setActivePluginRegistry(registry, cacheKey, "default");
+
+    expect(
+      __testing.getCompatibleActivePluginRegistry({
+        ...loadOptions,
+        runtimeOptions: {
+          allowGatewaySubagentBinding: true,
+        },
+      }),
     ).toBeUndefined();
   });