[STAC-25093] [stackstate-process-agent] Bump containerd dependency and rebuild process-agent

[kkaempf]

STAC-25093

Repo: https://github.com/StackVista/stackstate-process-agent

Affected image:

• quay.io/stackstate/stackstate-k8s-process-agent:a56e2a32

Findings to fix:

• HIGH CVE-2026-53488, github.com/containerd/containerd v1.7.32, fixed in 1.7.33, found in /opt/stackstate-agent/bin/agent/process-agent, reported by Trivy.
• HIGH GHSA-xhf5-7wjv-pqxp, same package/version/path, fixed in 1.7.33, reported by Grype.
• MEDIUM CVE-2026-47262, same package/version/path, fixed in 1.7.33, reported by Trivy.
• MEDIUM GHSA-jpcc-p29g-p8mq, same package/version/path, fixed in 1.7.33, reported by Grype.

Precise work:

• Update the Go dependency graph so github.com/containerd/containerd resolves to 1.7.33 or newer compatible patched version. Current local evidence showed go.mod had github.com/containerd/containerd v1.7.32 // indirect.
• Run the repo's Go tests/build checks.
• Publish a new dev process-agent image and make sure it is available to the agent chart promotion flow.

Acceptance criteria:

• New stackstate-k8s-process-agent image is published.
• Focused Trivy+Grype scan no longer reports the containerd HIGH/MEDIUM findings above.
• The fixed image tag lands in the latest dev agent chart.