feat(FN-2046): add accessible delete button to chat session items

- Add an inline delete button to each chat session item with an aria-label and Trash icon
- Prevent session selection when delete is clicked by stopping event propagation and opening the confirmation dialog
- Style the delete control to appear on hover/focus and remain visible on mobile for touch accessibility
- Add ChatView tests covering render behavior, confirmation flow, selection guard, delete action, and CSS visibility rules

packages/dashboard/app/components/ChatView.tsx

@@ -869,6 +869,17 @@ export function ChatView({ projectId, addToast }: ChatViewProps) {
                 }}
                 data-testid={`chat-session-${session.id}`}
               >
+                <button
+                  className="chat-session-delete-btn"
+                  onClick={(e) => {
+                    e.stopPropagation();
+                    setConfirmDelete(session.id);
+                  }}
+                  data-testid="chat-session-delete-btn"
+                  aria-label="Delete conversation"
+                >
+                  <Trash2 size={14} />
+                </button>
                 <div className="chat-session-title">{session.title || "Untitled"}</div>
                 <div className="chat-session-preview">
                   {session.lastMessagePreview || "No messages"}