Signals the start or end of a production shift on a specific line. SHIFT_STARTED events initialize the shift aggregate; SHIFT_ENDED events emit the final snapshot and clear state.

Key Fields

Field	Type	Description
eventType	enum	SHIFT_STARTED or SHIFT_ENDED
lineId	string	Production line identifier
shiftName	string	Human-readable shift name (e.g., “Morning”)
shiftTarget	int	Target number of pieces for this shift
timestamp	long	Event timestamp in milliseconds since epoch