Replace all inline avatar implementations (initials divs, Bot icons,
inline img tags) with the shared ActorAvatar component for consistency.
- Extend AssigneePicker with controlled open/onOpenChange, triggerRender,
and align props to support batch toolbar and other contexts
- Replace BatchAssigneePicker (~130 lines) with shared AssigneePicker
- Replace issue-detail sidebar inline DropdownMenu with AssigneePicker
- Add canAssignAgent filtering to issue-detail more menu
- Replace inline avatars in: filter panel, members-tab, agents page,
mention-hover-card, subscribers AvatarGroup
- Add data-slot="avatar" to ActorAvatar for AvatarGroup compatibility
- Add triggerRender prop to PropertyPicker for custom trigger elements
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>