Inconsistent State Management (Provider vs Riverpod)

### Description
The project currently uses both Provider and Riverpod for state management in different parts of the app. This creates inconsistency and confusion in the codebase.

### Problem
- Mixed usage of Provider and Riverpod
- Harder to maintain and onboard new contributors
- Inconsistent state management patterns
### Expected Fix
- Standardize state management to Riverpod only
- Replace all Provider usages with Riverpod equivalents

### Scope
- Identify all usages of Provider
- Refactor them using Riverpod (StateNotifier, AsyncNotifier, etc.)
- Ensure consistency across the app