feat: add package configuration to node config map

[t0mmylam]

Agents/steps need runtime context (agent version, package info). Previously node metadata CMs had only labels/annotations.

- Implementation:

• Add packages.json to each node’s “metadata” ConfigMap:
  • agentVersion (parsed from operator AgentImage)
  • packages: name, version, image, optional agentImageOverride/interrupt/configInterrupts
• Refresh/backfill via ValidateNodeConfigmaps
• Add AgentVersion() helper on SkyhookOperatorOptions.
• Introduce SkyhookMetadata intermediary (decoupled from CRD shape).
• Marshal the stable metadata instead of writing CR internals directly.

- Tests:

• Envtest: ensure skyhook namespace exists.
• Chainsaw: assert packages.json exists with agentVersion, package names/versions.