d701ae9ba2
When the tracker restarts, nodes' registrations are lost. The heartbeat loop was catching the 404 and printing a warning but never re-registering, leaving the node permanently invisible until manually restarted. Fix: on HTTP 404 heartbeat response, the loop re-posts the original registration payload to /v1/nodes/register and updates the node_id and heartbeat URL for subsequent beats. This also handles tracker expiry races. The register_payload is now passed into _start_heartbeat so the thread has everything needed for re-registration without reaching back into run_startup. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>