Implement the core reconciliation loop that connects Pod events to zone
lifecycle. Status subresource endpoints allow updating pod/node status
without triggering spec-level changes. The main binary now provides
`serve` (API server only) and `agent` (full node: API + scheduler +
controller + heartbeat) subcommands via clap.
- Status subresource: generic update_status in common.rs, PUT endpoints
for /pods/{name}/status and /nodes/{name}/status
- Pod controller: polls pods assigned to this node, provisions zones via
ZoneRuntime, updates status to Running/Failed, monitors zone health
- Node agent: registers host as a Node, sends periodic heartbeats with
Ready condition
- API client: lightweight reqwest-based HTTP client for controller and
node agent to talk to the API server
- Main binary: clap CLI with serve/agent commands, wires all components
together with graceful shutdown via ctrl-c
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
