feat: configure API dev proxy and improve useApiFetch error handling

- Add Nitro devProxy for local proxying of api/v1 and uploads to the backend server
- Improve useApiFetch to dynamically clear auth state and navigate to login on 401/403 errors
- Automatically strip Content-Type headers for multipart FormData upload request bodies
- Add css rule to fix Bootstrap Italia navbar link border display
- Add ts-expect-error tag to avoid type checking issues with bootstrap-italia bundle loading

nuxt.config.ts

@@ -20,6 +20,29 @@ export default defineNuxtConfig({
     url: 'http://localhost:3000',
     name: 'Visione - Un\'occhio per la sicurezza del cittadino.',
   },
+
+  nitro: {
+    devProxy: {
+      '/api/v1': {
+        target: 'https://bk.visione.studentindipendenti.it/api/v1',
+        changeOrigin: true,
+        headers: {
+          host: 'bk.visione.studentindipendenti.it',
+          origin: 'https://visione.studentindipendenti.it',
+          referer: 'https://visione.studentindipendenti.it/'
+        }
+      },
+      '/uploads': {
+        target: 'https://bk.visione.studentindipendenti.it/uploads',
+        changeOrigin: true,
+        headers: {
+          host: 'bk.visione.studentindipendenti.it',
+          origin: 'https://visione.studentindipendenti.it',
+          referer: 'https://visione.studentindipendenti.it/'
+        }
+      }
+    }
+  },
   
   css: [
     '@/assets/css/style.css',