- Replace avatar image from API with gradient avatar from twake-mui (#457)

- Display 2-letter initials (e.g., "JD" for "John Doe") instead of single letter
- Add getInitials helper function in avatarUtils for reusability
- Update Avatar in PeopleSearch, CalendarSearch, and Menubar components
- Remove avatarUrl prop usage across all Avatar components

src/utils/avatarUtils.ts

@@ -9,3 +9,21 @@ export function stringToGradient(str: string): string | undefined {
   if (!str) return undefined;
   return nameToColor(str);
 }
+
+/**
+ * Get initials from a name string (max 2 characters)
+ * @param name - Name string like "John Doe", "Alice", or "john.doe@email.com"
+ * @returns Initials like "JD", "A", or "J"
+ */
+export function getInitials(name: string): string {
+  if (!name) return "";
+
+  const trimmed = name.trim();
+  const words = trimmed.split(/\s+/).filter(Boolean);
+
+  if (words.length >= 2) {
+    return `${words[0][0]}${words[1][0]}`.toUpperCase();
+  }
+
+  return trimmed[0]?.toUpperCase() ?? "";
+}