fix: show avatar photos in all comment locations — speech bubble, panel, timeline

SpeechBubble.tsx: replace hardcoded gradient avatar with Avatar component using
comment.user?.avatarUrl + comment.user?.name. Also fixes review page new-comment
form avatar (user?.avatarUrl from auth context) and existing-comment card avatar
(already had the data but was not passing src prop).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/review/[assetId]/page.tsx

@@ -1147,7 +1147,7 @@ export default function ReviewPage() {
               }}
               className="flex gap-2"
             >
-              <Avatar name={user?.name ?? 'U'} size="sm" />
+              <Avatar name={user?.name ?? 'U'} src={user?.avatarUrl} size="sm" />
               <div className="flex-1 flex gap-2">
                 <textarea
                   className="input flex-1"
@@ -1262,7 +1262,7 @@ function CommentItem({
       }}
     >
       <div className="flex gap-2.5">
-        <Avatar name={name} size="sm" />
+        <Avatar name={comment.user?.name ?? 'U'} src={comment.user?.avatarUrl} size="sm" />
 
         <div className="flex-1 min-w-0">
           {/* Meta row */}

src/components/video-player/SpeechBubble.tsx

@@ -2,6 +2,7 @@
 
 import { Comment } from '@/lib/api';
 import { formatTimecode } from '@/lib/format';
+import { Avatar } from '@/components/ui/avatar';
 
 interface Props {
   comment: Comment;