fix(auth): LegalDocView v-alert role=note + trim back-link whitespace (review M-1/M-2)

Code-quality review of the legal stub pages: the always-present
informational v-alert defaulted to role=alert (assertive live-region) —
changed to role=note for a static advisory (WCAG 2.1 AA). Trimmed
cosmetic whitespace inside the back-link element.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/resources/js/views/legal/LegalDocView.vue

@@ -41,11 +41,11 @@ const doc = computed<LegalDoc>(() => (String(route.params.doc) === 'privacy' ? D
             <p class="text-body-2 text-medium-emphasis ma-0">{{ doc.intro }}</p>
         </header>
 
-        <v-alert type="info" variant="tonal" density="compact" data-testid="legal-stub-notice">
+        <v-alert type="info" variant="tonal" density="compact" role="note" data-testid="legal-stub-notice">
             Финальная редакция документа готовится и будет опубликована до запуска сервиса.
         </v-alert>
 
-        <RouterLink to="/login" class="text-body-2 text-primary legal-back"> ← Вернуться ко входу </RouterLink>
+        <RouterLink to="/login" class="text-body-2 text-primary legal-back">← Вернуться ко входу</RouterLink>
     </v-card>
 </template>