Task list assignee and filtering enhancements

Task list improvements: - Show Assignee initials in the form Creator -> Assignee. Example: RZ->JS . "->" is a little arrow. Clicking on Assignee opens an inline lookup drop down of users on this project - Change the filter by Creator to the filter by Assignee - the discs with initials next to task search - Add Assignee to filters - Add a color and/or badge difference to automated tasks (scheduled, webhooks), system generated tasks (broken builds, etc) and regular human tasks. Should save space. Propose several ideas - In the filter module enable choosing which columns to show - this is per user. Should be very easy to use as there are many fields

Creator→Assignee cell with inline picker, Assignee filter (strip+menu, /api/tasks/assignees), origin stripe+glyph, per-user Columns page. Quick gate green, visual check OK at 1440/448. PR #7674 queued in merge lane.