- Add SetupScreen with UI for server URL, username, and password input.
- Make SetupScreen the initial screen in the navigation graph.
- Implement secure credential storage using EncryptedSharedPreferences.
- Create CredentialsRepository and AuthRepository to manage credentials and auth tokens.
- Add LoginUseCase to handle the business logic for logging in.
- Implement a temporary Retrofit client in ItemRepository to handle login against a user-provided URL.
- Integrate login logic into SetupViewModel.
- Update all relevant project documentation and DI modules.
- Create stub files for all UI screens defined in the tech spec (InventoryList, ItemDetails, ItemEdit, LabelsList, LocationsList, Search).
- Add corresponding ViewModels for each new screen.
- Update `tech_spec/project_structure.txt` to include the new files and mark them as 'stub'.
- Update `tech_spec/tech_spec.txt` to reflect the current implementation status, changing feature statuses to 'in_progress'.
- Add the undocumented `SearchScreen` to the project specification.
- Add `*.hprof` files to `.gitignore` to exclude memory dumps from version control.
