🎨 Palette: [UX improvement] Add aria-expanded to interactive toggles

[secrooq]

💡 What: Added aria-expanded attributes to key interactive toggle buttons (mobile navigation menu, user profile dropdowns, and the floating support terminal widget), linking their ARIA states dynamically to their respective React state variables. Also added a missing aria-label to the mobile user profile toggle.

🎯 Why: To improve accessibility for screen reader users. Previously, these buttons did not communicate their open/closed state programmatically, making it difficult for visually impaired users to know if the associated menus or widgets were active or hidden.

📸 Before/After:
(Visuals remain unchanged. Code changes apply solely to HTML semantics.)

♿ Accessibility:

• Added aria-expanded={isOpen} to the Support Terminal toggle.
• Added aria-expanded={isMobileMenuOpen} to the main mobile hamburger menu.
• Added aria-expanded={isMobileProfileOpen} and aria-label="Toggle User Profile Menu" to the mobile user profile toggle.
• Added aria-expanded={isUserDropdownOpen} to the desktop user profile dropdown.

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PR created automatically by Jules for task 15520786789591062973 started by @secrooq

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