The collection 'plank_data' no longer needs to be created manually.
db.collection().add() auto-creates the collection on first write.
Changed push strategy from 'query-then-add' to 'add-first':
- add() succeeds → collection created, data stored
- add() fails (duplicate) → fall back to query + update
- .get() on non-existent collection now caught gracefully
Also switched updatedAt to db.serverDate() for consistent timestamps.
lc
ec52eb7b0d