Add Watch List Insights for Race Directors

Runners can subscribe to event Watch Lists to get alerts (e.g. results posted, reg opening, price increase coming, selling out, general info).

Right now, RDs can message Watch List subscribers—but can’t see who they are.

Feature request:

Show number of Watch List subscribers

Add basic insights (e.g. zip code, past participation)

Help RDs better understand and target interested runners before they register.