feat: dropdown added to profile

[AgustinSV]

Description

Created using Jalen's Dropdown as a reference. Adds a user profile dropdown to the header with quick access to common account actions. The dropdown displays the authenticated user’s avatar and provides navigation to profile-related pages, improving usability and discoverability of account settings.

Relevant Issues

N/A

How to Test

• Log in as a user.
• Click the user avatar in the header.
• Verify the dropdown opens.
• Click each menu item and confirm navigation works:
• Update Profile
• Change Password
• Manage Affiliations
• View Hours
• Notification Settings
• Language
• Click “Log out” and confirm the user is signed out and redirected to the home page.

Miscellaneous Notes

• Uses MUI Popover and MenuItem for the dropdown UI.
• Navigation is handled via the Next.js router.
• Ensures promises returned from navigation and sign-out are properly handled.
• Replaces the previous dropdown implementation.