[Performance] ReportActionAvatars — WorkspaceAvatar + policyID migration

[mountiny]

Parent tracking issue: #94584

Deliverables

Build:

• WorkspaceAvatar — Single, Subscript (workspace + optional user) layouts
• usePolicyAvatarFields hook (policyID, optional secondary accountID; uses policy announce/admins chat report when needed)

Migrate call sites:

• policyID branch of UserListItemContent

Notes

• Blocked by Layer 1 primitives (step 1)
• Each PR builds the component and migrates call sites in the same PR

Issue Owner

Current Issue Owner: @jmusial

[jmusial]

On hold for #95596

[melvin-bot]

This issue has not been updated in over 15 days. @jmusial, @roryabraham eroding to Monthly issue.

P.S. Is everyone reading this sure this is really a near-term priority? Be brave: if you disagree, go ahead and close it out. If someone disagrees, they'll reopen it, and if they don't: one less thing to do!