Fix infinite loading on login page

Fixed Redux saga selector to handle undefined user state during initial login.
The selector was trying to access state.user.data which was undefined before
first login, causing the saga to fail silently and loader to never hide.

Changed: state.user.data → state.user?.data || {}

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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