feat(core): make turn cancellation explicit

packages/subagent/subagent-inprocess/src/index.ts

@@ -153,7 +153,7 @@ export async function startInProcessRun(
 
   const onAbort = (): void => {
     flags.cancelled = true
-    child.cancel('subagent request aborted')
+    child.cancel({ kind: 'parent' })
   }
   request.signal.addEventListener('abort', onAbort, { once: true })
 

packages/subagent/subagent-inprocess/src/structured.ts

@@ -96,7 +96,7 @@ export function attachStructuredRuntime(childCtx: Context, schema: StructuredOut
   // Stop the child's turn once its output is captured. This monotonic serial
   // checkpoint runs after the ordinary continuation waterfall, its reason,
   // and late-steering folding, so no ordering trick can resume a finished run.
-  childCtx.on('agent/turn-stop', function (this: unknown): ContinuationStop | undefined {
+  childCtx.on('agent/turn-stop', function (this: unknown, _agent, _turn, _signal): ContinuationStop | undefined {
     return captured === undefined ? undefined : { action: 'stop' }
   })