feat: implement memory consolidation service with sleep cycle, add frontend visualization components, and integrate backend database orchestration.

Refactor: Simplify auth flow and improve neural mesh update synchronization

feat: replace sign up/sign in with single 'Enter' flow

fix: strict user isolation — remove all user_id IS NULL leaks

feat: clean slate on every sign-in — wipe all prior user data

fix: normalize usernames and ensure case-insensitive authentication

feat: Implement secure Authentication system with JWT and AuthScreen UI