Removed all legacy Pulse+ agent metrics infrastructure (cloud-relay) which has been
fully replaced by the new docker agent and temperature agent implementations.
Changes:
- Remove cloud-relay directory and all related binaries (relay, relay-linux, etc.)
- Remove Pulse+ documentation (AGENT_METRICS_IMPLEMENTATION.md, AGENT_METRICS_SETUP.md)
- Clean up pulse-relay references in workflows and release checklist
- Add audit log rotation documentation for sensor proxy hash-chained logs
- Update .gitignore to remove cloud-relay/ entry
The new docker and temp agents remain fully functional and unaffected by this cleanup.
