Collapse the front entry member list and use a time picker

[fullynocturnal]

Summary

Two usability fixes for the add/edit front entry sheet in History.

Shorter member list. Systems with a lot of members had to scroll past the whole roster to reach the time fields. The list now shows the first 5 members plus anyone already selected, with a "Show all (N)" / "Show less" toggle. Typing in the search field or picking a group filter still shows every match, so nobody is hidden while you're looking for them.

Time picker. The typed Hour/Min fields and AM/PM toggle are gone. The start and end times are now buttons next to their date buttons, and tapping one opens the Material 3 TimePickerDialog, the same way the date buttons open the date picker. The dial follows the device's 12/24 hour setting.

Notes

• Only the History sheet changes. The home screen switch sheet has its own member list and no time fields, so it's left alone.
• If a selected member beyond the first 5 gets unticked while the list is collapsed, they drop out of view. Expanding the list or searching brings them back.

Testing

• Open History, add a front entry with more than 5 members: only 5 show, plus the "Show all" button
• Edit an entry whose fronters are beyond the first 5: they still appear in the collapsed list
• Search and group filter still show every match
• Tapping the start or end time opens the time picker, and OK updates the button
• Cancel leaves the time unchanged
• Picking an end time before the start still shows the "end time must be after the start time" warning