Time Slot Generator from Weekly Working Hours

Generate every 30-minute appointment slot that falls inside a datetime range and inside that day's working hours.

Inputs:

• startDate and endDate: datetime strings "YYYY-MM-DD HH:MM" sharing one timezone.
• workingHours: a String[] where each entry is "day_of_week,start_time,end_time"; day_of_week is 0=Monday ... 6=Sunday and the times are "HH:MM". This table repeats every week.

Output: a String[] of slots sorted by start time, each formatted as "YYYY-MM-DD HH:MM|YYYY-MM-DD HH:MM" (start and end joined by |).

Slot rules:

• Each slot is exactly 30 minutes, generated in 30-minute increments counted from a working interval's start time.
• A slot must be fully inside a working interval for that weekday: slot_start >= work_start and slot_end <= work_end.
• A slot start must be >= startDate and a slot end must be <= endDate. A slot ending exactly at endDate is included; compare full datetimes, not just the date, on the boundary days.
• If startDate >= endDate, return an empty list.
• Overlapping or touching working intervals on the same weekday are merged so no duplicate slot is emitted (treat touching intervals like ...12:00 then 12:00... as one).