- Replace inline initials/Bot divs with ActorAvatar across all assignee UIs
- Replace issue-detail sidebar DropdownMenu with shared AssigneePicker
- Delete BatchAssigneePicker (~130 lines), reuse AssigneePicker in controlled mode
- Add controlled mode (open/onOpenChange), align, and triggerRender props to AssigneePicker/PropertyPicker
- Add canAssignAgent visibility check to issue-detail more menu
- Clean up unused imports (Bot, useAuthStore, useWorkspaceStore, etc.)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>