Refactor Docs, Clean Codebase, and Improve Config Consistency

[Ashad001]

This PR updates the backend and frontend docs, code, and config for better clarity and consistency. Key changes include:

• Docs:

  • Renamed all references from core_routes.py to session_routes.py
  • Updated deprecated init_database to init_db
  • Removed outdated testing and review notes
  • Improved startup and API instructions

• Code Cleanup:

  • Removed unused imports and redundant dependencies
  • Simplified comments for clarity

• Config Updates:

  • Switched to python -m app for server start
  • Dropped /redoc from API docs
  • Standardized JSON usage count examples

• Frontend:

  • Added missing headers import in webhooks/route.ts to align with latest App Router.