Subscription festival/vrat alerts — the COMPUTE half of subscription delivery/alerts, the festival-trigger companion to /alerts/dasha and /alerts/gochar. Computes, for the requested LOCATION, every Sanatan Dharma festival or vrat that falls inside the look-ahead window_days (each with its days_until and any ritual muhurat windows). Pure tithi / nakshatra / sankranti arithmetic over the deterministic festival engine (matched to Drik Panchang) — no astrological judgement, no fabrication; a festival is a calendar date, not a prediction.

Unlike the dasha/gochar alerts this feed is NOT personalised to a birth chart — a festival falls the same for everyone at a location — so it takes only a location + window, no birth details.

Scheduled DELIVERY (recurring push / email on a cadence) is a separate infrastructure layer that needs a worker + prod-config and is NOT performed here; this endpoint computes the alert content on demand and discloses that in the report's delivery_note. No scripture quoted.