QA (drb-qa-review) blockers: sdr_count defaulted to 1 for nodes that
never sent it, so the panel claimed 'reports 1 SDR (0 spare)'. It is now
None until reported, and the count is only quoted alongside a real
secondary_sdr_running report. Rows read 'Not reported' instead of
'Waiting for SDR' when the node hasn't said what's running (closes#187).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>