Upgrade agent-sandbox to v1.0.2

What would you like to be added:

Upgrade the agent-sandbox dependency from v0.4.6 to v1.0.2.

The upgrade can be done in the following steps:

• Finish and merge #446, and update its target version to v0.5.6. This moves AgentCube from the v1alpha1 APIs to v1beta1 and provides the required migration bridge for existing clusters.
• Upgrade Kubernetes dependencies to the versions required by agent-sandbox v1.0.2 in a separate PR.
• Upgrade agent-sandbox from v0.5.6 to v1.0.2 and handle the remaining v1.0 compatibility changes.
• Add upgrade E2E coverage for the v0.4.6 -> v0.5.6 -> v1.0.2 path.

Why is this needed:

AgentCube currently depends on agent-sandbox v0.4.6 and uses its v1alpha1 APIs.

agent-sandbox v1.0 removes the v1alpha1 APIs and requires existing v0.4.x installations to migrate their stored resources through v0.5.x before upgrading to v1.0.

#446 already contains most of the v1alpha1 -> v1beta1 adaptation, so it should be completed first and used as the base for the v1.0.2 upgrade.

Start by reviewing #446 and its v1alpha1-to-v1beta1 migration work, then identify the Kubernetes dependency versions required by agent-sandbox v1.0.2. Follow the upgrade sequence from v0.4.6 through v0.5.6 to v1.0.2 and inspect the existing E2E tests. Done means the dependency upgrade is compatible and the full migration path has upgrade E2E coverage.