Live numbers for the experiments dashboard

Depends on the self-hosted Umami analytics API: the runtime env UMAMI_URL, UMAMI_USERNAME and UMAMI_PASSWORD must be set. The server logs in at <UMAMI_URL>/api/auth/login, caches the token in-process and logs in again once on a 401.

For every experiment in EXPERIMENTS (src/lib/experiments.ts) it queries /api/websites/0e838cbf-d608-4400-b2c7-4557f2613cec/metrics?type=event and /event-data/values per event and property, for the window from shippedAt 00:00 UTC to now. Experiments with a pb check additionally get PocketBase cohort stats from users and wireframe_states; the recent cohort covers at most the last 13 days because unverified accounts are pruned after 14.

Any failure (Umami not configured, login or query failed, PocketBase error) answers 502.