Backend:
- New GET/PUT /api/me endpoint to read and update the authenticated
user's profile (currently display_name). UserStore.UpdateDisplayName.
- Wired into the authed router.
App:
- New SettingsScreen + SettingsViewModel with five sections:
* Account & Sync: login status, email, server URL, logout, connect.
* Profile: edit display name (pushed to PUT /api/me when logged in).
* Appearance: System / Light / Dark theme switch, persisted in
SessionManager and applied via MitbringslTheme(sessionManager).
* Data: 'Reset local data' wipes Room tables (server data kept).
* About: version, 'Developed by Janik Dietz', and credits to
GLM-5.2 + Gemini 3.6 Flash.
- Theme.kt now reads the user's theme preference (StateFlow) instead
of only the system default; MainActivity passes SessionManager in.
- Navigation: new SettingsNavKey; settings gear icon in ListsScreen
top bar; Settings links back to the Sync/Account screen.
- DTOs/API: UpdateMeRequestDto + getMe()/updateMe() for /api/me.