feat: add tap-to-profile navigation for avatar in feed list (#130)

Add .to modifier to AvatarView in FeedItemView so users can tap on
avatars in the feed list to navigate to the user's profile page.
This matches the existing behavior in ReplyItemView.

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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: graycreate

V2er/View/Feed/FeedItemView.swift

@@ -15,6 +15,7 @@ struct FeedItemView<Data: FeedItemProtocol>: View {
         VStack(spacing: 0) {
             HStack(alignment: .top) {
                 AvatarView(url: data.avatar)
+                    .to { UserDetailPage(userId: data.userName.safe) }
                 VStack(alignment: .leading, spacing: 2) {
                     Text(data.userName.safe)
                         .font(.footnote)