feature: localization's first implmentation done. all frontend hardcoded text is now localized.

frontend/src/app/[locale]/(public)/login/page.tsx

@@ -81,7 +81,7 @@ export default function LoginPage() {
           {t('signInTitle')}
         </h2>
         <p className="mt-2 text-center text-sm text-text-secondary">
-          Or{' '}
+          {tCommon('or')}{' '}
           <Link href="/register" className="font-medium text-primary hover:opacity-90">
             {t('startTrialLink')}
           </Link>
@@ -95,7 +95,7 @@ export default function LoginPage() {
               label={t('email')}
               {...register('email')}
               type="email"
-              placeholder="you@example.com"
+              placeholder={t('emailPlaceholder')}
               error={errors.email?.message}
               icon={<Mail className="h-5 w-5 icon-flat" />}
             />
@@ -103,7 +103,7 @@ export default function LoginPage() {
               label={t('password')}
               {...register('password')}
               type="password"
-              placeholder="••••••••"
+              placeholder={t('passwordPlaceholder')}
               error={errors.password?.message}
               icon={<Lock className="h-5 w-5 icon-flat" />}
             />