v0.4.2

## 🚀 Announcing Agent Sandbox v0.4.2!

We are excited to announce the release of **Agent Sandbox v0.4.2**!

This release introduces significant enhancements to the **Python SDK** with asynchronous operations, improves **controller stability** through optimized warm pool management, and strengthens **observability** with precision latency tracking and debug endpoints. Additionally, the Python SDK expands **lifecycle management** capabilities with native support for suspend and resume using GKE Pod snapshots, alongside a wealth of new documentation and examples to accelerate AI agent development.

### Key Highlights

*   **Python SDK Advancements**: Introduced a new **asynchronous Python client** to enable non-blocking sandbox operations. The SDK now also supports specifying `spec.lifecycle` in `SandboxClaim` at creation time and provides new methods for status retrieval and environment variable injection.
*   **Enhanced Lifecycle & Snapshots**: Implemented [**suspend and resume** functionality in Python SDK](clients/python/agentic-sandbox-client/k8s_agent_sandbox/gke_extensions/snapshots) leveraging GKE Pod snapshots, allowing for stateful sandbox persistence. Users can also configure **auto-cleanup** based on boolean flags for better resource management.
*   **Core Stability & Warm Pool Optimization**: The `SandboxWarmPool` now automatically **recreates sandboxes upon template updates**. Retrieval performance is significantly improved with a new **queue-based mechanism** for warm sandbox adoption.
*   **Precision Observability & Debugging**: Improved the precision of **controller startup latency** metrics using event predicates. A new **`fgprof` debug endpoint** has been added for advanced Off-CPU time analysis to assist in performance tuning.
*   **Expanded Documentation & Examples**: Launched a new quickstart example and a dedicated examples section on the website. Architecture diagrams have been updated to highlight extension points, and new guides for OTel Collector deployment are now available.

### Installation

#### Core & Extensions

```bash
# To install only the core components:
kubectl apply -f https://github.com/kubernetes-sigs/agent-sandbox/releases/download/v0.4.2/manifest.yaml

# To install the extensions components:
kubectl apply -f https://github.com/kubernetes-sigs/agent-sandbox/releases/download/v0.4.2/extensions.yaml
```

#### Python SDK

```bash
pip install k8s-agent-sandbox==0.4.2
```

---

## Contributors

A huge thank you to all the contributors who made this release possible!

@AndyJCai, @igooch, @rayowang, @xiaoj655, @vicentefb, @shrutiyam-glitch, @SHRUTI6991, @aleks-stefanovic, @dongjiang1989, @aditya-shantanu, @brandonroyal, @volatilemolotov, @Iceber, @framsouza, @Pepper-rice, @chw120, @justinsb, @janetkuo, @kincoy, @dependabot, @Oneimu, @wllbo

## New Contributors
* @AndyJCai made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/510
* @rayowang made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/535
* @xiaoj655 made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/371
* @framsouza made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/477
* @Pepper-rice made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/469
* @dependabot[bot] made their first contribution in https://github.com/kubernetes-sigs/agent-sandbox/pull/625

**Full Changelog**: https://github.com/kubernetes-sigs/agent-sandbox/compare/v0.3.10...v0.4.2