- Created Umzugsliste_Admin_Menu class with singleton pattern
- Top-level menu 'Umzugsliste' with dashicons-list-view icon
- Position 25 (below Comments, above Appearance)
- Capability: edit_posts (editors and above)
- Submenu 'Einträge' links to CPT list view
- Submenu 'Einstellungen' shows placeholder (Phase 3)
- Removed duplicate top-level menu item
- Created Umzugsliste_CPT class with singleton pattern
- Registered umzugsliste_entry post type
- German labels (Einträge, Eintrag)
- Settings: public=false, show_ui=true, show_in_menu=false
- Supports title field only (custom fields in Phase 6)
- Registered on init hook
