Feat: Responsive messaging interface - Elise

[huntingforelise]

Summary

Built a responsive messaging interface for the leboncoin technical test, including conversation browsing, message sending, contact search, new conversation creation, and robust error handling.

Highlights

• Implemented desktop and mobile messaging layouts
• Added conversation search and contact suggestions
• Prevented duplicate conversations by opening existing threads
• Added loading, empty, disabled, and retryable error states
• Preserved message drafts after failed sends
• Added message length and empty-message safety checks
• Updated conversation previews after successful sends
• Added Jest/React Testing Library coverage and Playwright E2E checks
• Documented architecture, styling choices, performance notes, accessibility, and future React Query/Tailwind considerations

Verification

• npm test -- --runInBand
• npm run build
• npm run test:e2e