[No QA] refactor: OptionRowLHN — Avatar rename + context wiring

[mountiny]

Part of

#89946 — OptionRowLHN compound component decomposition

Step

4 of 12 — depends on #89947 (Provider + context interface).

What

• Rename OptionRowAvatar.tsx → Avatar.tsx (drop OptionRow prefix per naming convention)
• Update export to OptionRow.Avatar
• Wire subscriptAvatarBorderColor and secondaryAvatarBackgroundColor to read hover/focus state from RowContext instead of receiving them as props
• Update all import sites

Why

Completes the rename convention agreed for the compound family and removes the last prop-drilling of background colors into the avatar.

Acceptance criteria

• File is Avatar.tsx, export is OptionRow.Avatar
• No subscriptAvatarBorderColor / secondaryAvatarBackgroundColor props on the public interface; values derived from context
• No visible behavior or style changes

Issue Owner

Current Issue Owner: @DylanDylann