[Due for payment 2026-07-17] [M1] Split Avatar into primitives

[mountiny]

Problem

The shared Avatar component is monolithic: user vs workspace forking via type, image vs icon vs letter-avatar rendering, and source/error resolution all live in one file (~175 lines). This blocks removing the type prop and migrating call sites to focused components.

Solution

Extract focused pieces under src/components/Avatar/:

• AvatarUser.tsx, AvatarWorkspace.tsx, AvatarBody.tsx
• AvatarImage.tsx, AvatarIcon.tsx, AvatarInitials.tsx
• useUserAvatarSource.ts, useWorkspaceAvatarSource.ts, useAvatarLoadError.ts
• types.ts
• index.tsx facade preserving today's public API

Add unit tests in tests/unit/AvatarTest.tsx.

PR

#95050

Dependencies

Unblocks M3 and M4. M2 (size unification) can land independently but should coordinate merge order to reduce conflicts.

Issue Owner

Current Issue Owner: @jmusial