fix: support virtual-hosted S3 URLs for avatar storage (#330)

Avatar images failed to load with 403 on Tigris and newer AWS S3 buckets
because getAvatarUrl only constructed path-style URLs. Modern S3-compatible
providers require virtual-hosted URLs (bucket.domain/key).

Add NEXT_PUBLIC_STORAGE_DOMAIN env var to signal URL style:
- If set: virtual-hosted URL (Tigris, AWS S3)
- If not set: path-style URL (MinIO, LocalStack) - backward compatible

Add vitest and tests for getAvatarUrl behavior.

Co-authored-by: Sachin Divekar <sachin.divekar@remiges.tech>

apps/web/src/utils/helpers.ts

@@ -52,5 +52,13 @@ export const getAvatarUrl = (imageOrKey: string | null) => {
     return imageOrKey;
   }
 
-  return `${env("NEXT_PUBLIC_STORAGE_URL")}/${env("NEXT_PUBLIC_AVATAR_BUCKET_NAME")}/${imageOrKey}`;
+  const bucket = env("NEXT_PUBLIC_AVATAR_BUCKET_NAME");
+  const storageDomain = env("NEXT_PUBLIC_STORAGE_DOMAIN");
+
+  if (storageDomain) {
+    return `https://${bucket}.${storageDomain}/${imageOrKey}`;
+  }
+
+  const storageUrl = env("NEXT_PUBLIC_STORAGE_URL");
+  return `${storageUrl}/${bucket}/${imageOrKey}`;
 };