tasks: add detached runtime plugin registration contract (#68915)

* tasks: register detached runtime plugins

* tasks: harden detached runtime ownership

* tasks: extract detached runtime contract types

* changelog: note detached runtime contract

* changelog: attribute detached runtime contract

test/helpers/plugins/plugin-api.ts

@@ -41,6 +41,7 @@ export function createTestPluginApi(api: TestPluginApiInput = {}): OpenClawPlugi
     registerContextEngine() {},
     registerCompactionProvider() {},
     registerAgentHarness() {},
+    registerDetachedTaskRuntime() {},
     registerMemoryCapability() {},
     registerMemoryPromptSection() {},
     registerMemoryPromptSupplement() {},