Redesign login page (#5)

- Rename header to "Assistant System", subtitle to "Вхід у систему"
- Glassmorphism card over animated gradient backdrop, logo mark
- Password visibility toggle, larger inputs, focus rings

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/auth/LoginPage.tsx

@@ -19,6 +19,7 @@ export function LoginPage() {
 
   const [email, setEmail] = useState('')
   const [password, setPassword] = useState('')
+  const [showPassword, setShowPassword] = useState(false)
   const [submitting, setSubmitting] = useState(false)
   const [formError, setFormError] = useState<string | null>(null)
 
@@ -45,10 +46,22 @@ export function LoginPage() {
 
   return (
     <div className="login-page">
+      <div className="login-backdrop" aria-hidden="true">
+        <span className="login-blob login-blob--a" />
+        <span className="login-blob login-blob--b" />
+        <span className="login-blob login-blob--c" />
+      </div>
+
       <div className="login-card">
         <div className="login-header">
-          <h1>lux_fiscal</h1>
-          <p>Вход в систему фискализации заказов</p>
+          <div className="login-logo" aria-hidden="true">
+            <svg viewBox="0 0 24 24" width="26" height="26" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+              <path d="M12 3l7 4v5c0 4.5-3 8-7 9-4-1-7-4.5-7-9V7l7-4z" />
+              <path d="M9 12l2 2 4-4" />
+            </svg>
+          </div>
+          <h1>Assistant System</h1>
+          <p>Вхід у систему</p>
         </div>
 
         <form onSubmit={handleSubmit} noValidate>
@@ -74,16 +87,31 @@ export function LoginPage() {
 
           <div className="login-field">
             <label htmlFor={passwordId}>Пароль</label>
-            <input
-              id={passwordId}
-              type="password"
-              autoComplete="current-password"
-              required
-              value={password}
-              disabled={submitting}
-              onChange={(e) => setPassword(e.target.value)}
-              placeholder="••••••••"
-            />
+            <div className="login-password">
+              <input
+                id={passwordId}
+                type={showPassword ? 'text' : 'password'}
+                autoComplete="current-password"
+                required
+                value={password}
+                disabled={submitting}
+                onChange={(e) => setPassword(e.target.value)}
+                placeholder="••••••••"
+              />
+              <button
+                type="button"
+                className="login-toggle"
+                onClick={() => setShowPassword((v) => !v)}
+                aria-label={showPassword ? 'Скрыть пароль' : 'Показать пароль'}
+                aria-pressed={showPassword}
+              >
+                <svg viewBox="0 0 24 24" width="18" height="18" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
+                  <path d="M2 12s3.5-7 10-7 10 7 10 7-3.5 7-10 7S2 12 2 12z" />
+                  <circle cx="12" cy="12" r="3" />
+                  {showPassword && <path d="M3 3l18 18" />}
+                </svg>
+              </button>
+            </div>
           </div>
 
           <button type="submit" className="login-submit" disabled={submitting}>