Users couldn't clear the time part of a task's due date because the
"clear time" button only toggled includeTime=false without signalling
the picker to finish. Call done() when clearing the time so the picker
closes/emits the updated value, ensuring the task's has_time state is
updated and the UI reflects a date-only value.
Replace the hours==0 && minutes==0 heuristic with an explicit has_time
bool field on Task. Existing files without the field deserialize as false
(date-only), preserving current behavior. Frontend components pass and
receive has_time through DateTimePicker's onchange callback.
Replace inline task editing with a full-viewport detail panel that
slides in from the right. Includes editable title, description, custom
calendar-based date/time picker (bottom sheet), kebab menu with delete,
and mark complete/restore button. Simplify TaskItem to remove inline
editing and kebab menu, add chevron hint and onopen callback. Use list
icon for drawer toggle instead of back arrow.
