Previously install.sh only wrote an empty config with placeholder agent_id/
api_key and printed manual next-steps — users had to curl register themselves
and paste the values, which often failed.

Now the script:
- POSTs to /api/agent/register and parses agent_id + api_key (sed, no jq needed)
- writes them straight into config.yaml (chmod 600)
- uses the correct plugins.laravel.log_paths structure (not top-level laravel:)
- uses 'nawasara-agent run --config' in the systemd ExecStart (run subcommand)
- starts the service automatically
- fails loudly with the dashboard response if registration doesn't return keys