* 🗑️ chore: remove unused helpers folder

* 📝 docs: Update Lobe Chat API to latest architecture

* 📝 docs: Update contributing guidelines to include style checking section and improve clarity

* 📝 docs: Update application description from "AI conversation" to "AI chat" for clarity in architecture documentation

* 📝 docs: Update State Management introduction to clarify merging process in useSessionStore hook

* 📝 docs: optimize content order