fix: rename 'Your Name' to 'Annotator', make read-only, auto-populated from OAuth

app/components/AnnotationModal.js

@@ -78,14 +78,13 @@ export default function AnnotationModal({
 
                     {/* Annotator name */}
                     <div className="form-group">
-                        <label htmlFor="annotator-name">Your Name</label>
+                        <label htmlFor="annotator-name">Annotator</label>
                         <input
                             id="annotator-name"
                             type="text"
                             className="form-input"
-                            placeholder="Enter your name"
-                            value={annotatorName}
-                            onChange={(e) => onAnnotatorChange(e.target.value)}
+                            value={annotatorName || 'Not signed in'}
+                            readOnly
                         />
                     </div>
                 </div>