Real time activity feed for platform events

[parkerwinner]

Description: Create activity feed showing recent platform events (trades, listings, proposals) with filtering and real-time updates.

File Changes:

• frontend/src/components/ActivityFeed.tsx - Create feed component
• frontend/src/hooks/useActivityFeed.ts - Add feed hook

Branch: feature/activity-feed

PR Title: Implement real-time platform activity feed

Additional Info: Group activities by time, add event icons, support filtering by event type, implement infinite scroll, add real-time updates via WebSocket.

[Ebuka321]

@Ebuka321 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Good day. Please can i work on these issue.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ebuka321 to this issue.