feat(agent-presets): enable background Codex and Claude Code subagent tasks

examples/acp-agent/tests/fixtures/subagent/subagent-codex/cordis.yml

@@ -1,4 +1,4 @@
-# Test-only composition of the public opt-in provider and foreground tool.
+# Test-only composition of the public opt-in provider and one-shot task tool.
 # The owning e2e boots this tree but never invokes the model or Codex.
 - id: fixture
   name: './fixture.ts'
@@ -17,7 +17,7 @@
   config:
     provider: codex
     toolName: subagent_codex
-    enableRunInBackground: false
+    backgroundMode: one-shot
     maxDepth: 'provider-managed'
 
 - id: agent-spine

examples/acp-agent/tests/fixtures/subagent/subagent-codex/driver.ts

@@ -31,6 +31,10 @@ try {
   if (typeof properties !== 'object' || properties === null || Array.isArray(properties)) {
     throw new Error('subagent_codex tool has invalid parameter properties')
   }
+  const taskTools = ctx.tools.schemas()
+    .map(schema => schema.name)
+    .filter(name => name === 'task_kill' || name === 'task_list' || name === 'task_output')
+    .sort()
 
   process.stdout.write(`${JSON.stringify({
     providers: ctx.subagents.list(),
@@ -44,6 +48,7 @@ try {
       parameterNames: Object.keys(properties).sort(),
       required: tool.parameters.required,
     },
+    taskTools,
     starts,
   })}\n`)
 } finally {