Refactor authentication and theme context usage

- Moved authentication hooks and context to a dedicated hooks directory.
- Updated imports in various components and pages to use the new hooks.
- Created AuthContext and ThemeContext for better state management.
- Refactored ThemeProvider to utilize the new ThemeContext.
- Cleaned up sidebar and button components for consistency and readability.
- Ensured all components are using the latest context and hooks for authentication and theme management.

src/hooks/use-theme.ts

@@ -0,0 +1,11 @@
+import { useContext } from 'react'
+import { ThemeProviderContext } from '@/contexts/ThemeContext'
+
+export const useTheme = () => {
+  const context = useContext(ThemeProviderContext)
+
+  if (context === undefined)
+    throw new Error('useTheme must be used within a ThemeProvider')
+
+  return context
+}