[FEAT]: HTTP-only Cookie-based Auth + Refactor + Minor Bugs

[Spiral-Memory]

As an EmbeddedChat developer

I need to: Implement HTTP-only cookie authentication using EmbeddedChat RC-app

So that: Users feel more secure since no JavaScript-accessible token will be stored in local/session/cookie storage

Acceptance Criteria:

• [x] Implement HTTP-only cookie-based authentication
• [x] EC Component Refactor
• [x] Bug fixes