Complete household task management system behind task_users auth group:
- Task CRUD with recurring schedules, assignees, tags, and optional difficulty
- Blobcat SVG sticker rewards on completion, rarity weighted by difficulty
- Sticker collection page with calendar view and progress tracking
- Redesigned cards with left accent urgency strip, assignee PFP, round check button
- Weekday-based due date labels for tasks within 7 days
- Tasks link added to homepage LinksGrid
