fix: comprehensive UI/UX accessibility and usability improvements

Public site: skip-to-content link, mobile menu focus trap + Escape key,
aria-current on nav, keyboard navigation for carousels/tabs/articles,
ARIA roles (tablist/tab/tabpanel, combobox/listbox, region, dialog),
form labels + aria-describedby, 44px touch targets, semantic HTML
(<time>, <del>), prefers-reduced-motion on Hero scroll hijack,
mobile schedule filters, URL hash sync on scroll for correct refresh.

Admin panel: password toggle aria-label, toast aria-live regions,
SelectField keyboard navigation (Arrow/Enter/Escape), aria-invalid
on validation errors, sidebar hamburger aria-label/expanded,
nav aria-label, ArrayEditor aria-expanded on collapsible items.

src/components/ui/SignupModal.tsx

@@ -153,7 +153,7 @@ export function SignupModal({
         <button
           onClick={handleClose}
           aria-label="Закрыть"
-          className="absolute right-4 top-4 flex h-8 w-8 items-center justify-center rounded-full text-neutral-500 transition-colors hover:bg-white/[0.06] hover:text-white cursor-pointer"
+          className="absolute right-4 top-4 flex h-11 w-11 items-center justify-center rounded-full text-neutral-500 transition-colors hover:bg-white/[0.06] hover:text-white cursor-pointer"
         >
           <X size={18} />
         </button>
@@ -223,29 +223,40 @@ export function SignupModal({
             </div>
 
             <form onSubmit={handleSubmit} className="space-y-3">
-              <input
-                type="text"
-                value={name}
-                onChange={(e) => setName(e.target.value)}
-                placeholder="Ваше имя"
-                required
-                className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] px-4 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
-              />
+              <div>
+                <label htmlFor="signup-name" className="sr-only">Ваше имя</label>
+                <input
+                  id="signup-name"
+                  type="text"
+                  value={name}
+                  onChange={(e) => setName(e.target.value)}
+                  placeholder="Ваше имя"
+                  required
+                  aria-required="true"
+                  className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] px-4 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
+                />
+              </div>
               <div className="relative">
+                <label htmlFor="signup-phone" className="sr-only">Телефон</label>
                 <PhoneIcon size={14} className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500" />
                 <input
+                  id="signup-phone"
                   type="tel"
                   value={phone}
                   onChange={(e) => handlePhoneChange(e.target.value)}
                   placeholder="+375 (__) ___-__-__"
                   required
+                  aria-required="true"
+                  aria-describedby={error && error !== "network" ? "error-phone" : undefined}
                   className="w-full rounded-xl border border-white/[0.08] bg-white/[0.04] pl-9 pr-4 py-3 text-sm text-white placeholder-neutral-500 outline-none transition-colors focus:border-gold/40 focus:bg-white/[0.06]"
                 />
               </div>
               <div className="grid grid-cols-2 gap-2">
                 <div className="relative">
+                  <label htmlFor="signup-instagram" className="sr-only">Instagram (необязательно)</label>
                   <span className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500 text-xs">@</span>
                   <input
+                    id="signup-instagram"
                     type="text"
                     value={instagram}
                     onChange={(e) => setInstagram(e.target.value.replace(/^@/, ""))}
@@ -254,8 +265,10 @@ export function SignupModal({
                   />
                 </div>
                 <div className="relative">
+                  <label htmlFor="signup-telegram" className="sr-only">Telegram (необязательно)</label>
                   <span className="absolute left-3 top-1/2 -translate-y-1/2 text-neutral-500 text-xs">@</span>
                   <input
+                    id="signup-telegram"
                     type="text"
                     value={telegram}
                     onChange={(e) => setTelegram(e.target.value.replace(/^@/, ""))}
@@ -266,7 +279,7 @@ export function SignupModal({
               </div>
 
               {error && error !== "network" && (
-                <p className="text-sm text-red-400">{error}</p>
+                <p id="error-phone" className="text-sm text-red-400">{error}</p>
               )}
 
               <button