Isolate nested agent sessions

## What changed OpenClaw added session isolation for nested agent runs. The update scopes each nested task to its own target session so one long-running sub-agent cannot block unrelated conversations at the gateway.

The change rolled out on 19 May 2026 and requires no new configuration. Existing YAML setups continue to work while the gateway now enforces per-session boundaries automatically.

## Why it matters Nested agents often spawn browser or shell tasks that run for minutes. Without isolation, a single heavy job could stall every active chat thread on the same instance.

This fix reduces cross-talk between parallel workflows. It matters most for Vibe Builders who keep one OpenClaw instance tied to WhatsApp and Slack at the same time.

## How to use it Update to the latest release through the CLI with the standard pull command. Restart the gateway container or process after the update completes.

No extra flags or YAML keys are needed. Test by starting two separate conversations and triggering a long nested task in one to confirm the other stays responsive.

## Watch for Monitor gateway logs for any new session-scoping errors during heavy browser runs. The next expected move is explicit per-skill resource limits so runaway skills can be capped without touching the whole agent.