HA event triggers expose the payload as trigger.event.data, not
trigger.payload; fix the blueprint, its tests, and the README
examples, with a regression guard.
README gains the blueprint section: all four blueprints, their
inputs, the wiring table to the options-flow notification settings,
the celebration helper setup, event/sensor payload reference, and a
copy-pasteable example package. Tests assert every event trigger
references a real NestQuest event and no reminder is produced for an
absent child.
quest_completed and quest_uncompleted fire on actual transitions with
documented payloads; child_day_complete fires when a completion clears
the child's day; quest_missed is defined as Feature 11's contract.
Payloads documented in the README for automation authors.