Enhance accessibility and improve form semantics across multiple pages

- Added `htmlFor` attributes to labels for better accessibility in Calendar, Dashboard, GuestJoin, Login, Register, RoomDetail, and Settings pages.
- Included `aria-hidden` attributes for icons to improve screen reader experience.
- Set `autoComplete` attributes for input fields to enhance user experience during form filling.
- Implemented `role` and `aria` attributes for radio groups and buttons to improve accessibility compliance.

src/components/Sidebar.jsx

@@ -60,6 +60,7 @@ export default function Sidebar({ open, onClose }) {
             <BrandLogo size="md" className="flex-1 min-w-0" />
             <button
               onClick={onClose}
+              aria-label={t('common.close')}
               className="lg:hidden p-1.5 rounded-lg hover:bg-th-hover text-th-text-s transition-colors"
             >
               <X size={18} />
@@ -112,7 +113,7 @@ export default function Sidebar({ open, onClose }) {
                 {user?.avatar_image ? (
                   <img
                     src={`${api.defaults.baseURL}/auth/avatar/${user.avatar_image}`}
-                    alt="Avatar"
+                    alt=""
                     className="w-full h-full object-cover"
                   />
                 ) : (