feat(contact): add toast notifications for form feedback

- Add toast notifications for contact form success/error responses
- Add toast notifications for backend errors in AppFooter
- Add accessibility explanation for honeypot field
- Add loading state to contact form submit button
- Add i18n translations for toast messages (en/fr)
- Fix honeypot input missing v-model binding

app/composables/useBackend.ts

@@ -7,7 +7,7 @@ export const useBackend = () => {
 
   const getMeta = (): UseApiResponse<MetaResponse> => api.get<MetaResponse>('/meta');
   const postContact = (): UseApiResponse<ContactResponse, ContactRequest> =>
-    api.post<ContactResponse, ContactRequest>('/contact', undefined, true);
+    api.post<ContactResponse, ContactRequest>('/contact', undefined, false);
 
   return { getMeta, postContact };
 };