do to formatters

apps/website/lib/formatters/AvatarFormatter.ts

@@ -0,0 +1,38 @@
+/**
+ * AvatarDisplay
+ *
+ * Deterministic mapping of avatar-related data to display formats.
+ */
+
+export class AvatarFormatter {
+  /**
+   * Converts binary buffer to base64 string for display.
+   */
+  static bufferToBase64(buffer: ArrayBuffer): string {
+    const bytes = new Uint8Array(buffer);
+    let binary = '';
+    for (let i = 0; i < bytes.byteLength; i++) {
+      binary += String.fromCharCode(bytes[i]);
+    }
+    return btoa(binary);
+  }
+
+  /**
+   * Determines if avatar data is valid for display.
+   * Accepts base64-encoded string buffer.
+   */
+  static hasValidData(buffer: string, contentType: string): boolean {
+    return buffer.length > 0 && contentType.length > 0;
+  }
+
+  /**
+   * Formats content type for display (e.g., "image/png" → "PNG").
+   */
+  static formatContentType(contentType: string): string {
+    const parts = contentType.split('/');
+    if (parts.length === 2) {
+      return parts[1].toUpperCase();
+    }
+    return contentType;
+  }
+}