Backfill Agency Names

Sweep every agency install row and resolve a real name via GHL.

Useful after legacy data: hit this once and every row that was rendering its raw company_id gets its real agency name written back into settings.agency_name + settings.company_name. Subsequent admin page loads then render the real names directly without needing per-request enrichment.

Capped at limit rows per call (default 200) so the endpoint never turns into a multi-minute blocking sweep.