fix: add fallback for missing group names in Move Faces Modal

Problem:
- Some groups may not have name field
- Display would show blank or undefined

Solution:
- Add fallback: c.name || 'Unnamed Group'
- Add fallback: c.trace_count || 0
- Ensures always shows meaningful text

Impact:
- Move Faces Modal now always shows group names
- No blank entries even with incomplete data

src/views/PeopleView.vue

@@ -321,8 +321,8 @@
                 <ellipse cx="60" cy="105" rx="40" ry="25" fill="var(--border-color)"/>
               </svg>
             </div>
-            <span class="ms-merge-face-name">{{ c.name }}</span>
-            <span class="ms-merge-face-count">{{ c.trace_count }} faces</span>
+            <span class="ms-merge-face-name">{{ c.name || 'Unnamed Group' }}</span>
+            <span class="ms-merge-face-count">{{ c.trace_count || 0 }} faces</span>
           </div>
         </div>
       </div>