Sort by date (due date, creation date) #140

Description

Add a sort option to the Upcoming screen that allows users to change the order of tasks within each day group. By default, tasks are sorted by due date, soonest first.

The sort option is presented as a dropdown or pill selector next to the filter dropdowns at the top of the Upcoming screen. Available sort options are:

• Due: Soonest (default) — tasks with the closest due date first
• Due: Latest — tasks with the furthest due date first
• Created: Oldest — tasks created earliest first
• Created: Newest — tasks created most recently first

The selected sort option persists for the session but resets to "Due: Soonest" on app restart.

Depends on #138 (Upcoming screen: day-grouped task list), #139 (Upcoming screen: pill-shaped filter dropdowns).

Scope

In scope: sort option UI (Due: Soonest, Due: Latest, Created: Oldest, Created: Newest), sort logic in UpcomingViewModel, defaulting to Due: Soonest, session-persistent sort selection, and string resources.

Out of scope: sort by priority (separate ticket), sort by proximity (separate ticket #29), sort persistence across app restarts.

Acceptance criteria

• GIVEN the user is on the Upcoming screen
  WHEN the screen renders
  THEN a sort option selector is shown near the filter dropdowns with options: Due: Soonest, Due: Latest, Created: Oldest, Created: Newest
• GIVEN the sort options are displayed
  WHEN the screen first loads
  THEN "Due: Soonest" is selected by default
• GIVEN the user selects "Due: Soonest"
  WHEN the selection occurs
  THEN tasks within each day group are sorted with the closest due date first
• GIVEN the user selects "Due: Latest"
  WHEN the selection occurs
  THEN tasks within each day group are sorted with the furthest due date first
• GIVEN the user selects "Created: Oldest"
  WHEN the selection occurs
  THEN tasks within each day group are sorted by creation date, oldest first
• GIVEN the user selects "Created: Newest"
  WHEN the selection occurs
  THEN tasks within each day group are sorted by creation date, newest first
• GIVEN the user changes the sort option
  WHEN the task list updates
  THEN the grouping by day is preserved and only the order within groups changes
• GIVEN the user has selected a different sort option
  WHEN the app is restarted
  THEN the sort option resets to "Due: Soonest"
• GIVEN user-visible text appears in the sort option selector
  WHEN the app renders it
  THEN all visible text comes from string resources