Component integration tests: SetupScreen, SettingsOverlay, HistorySidebar, PlaybackBar, SearchBox

[thedavidweng]

Problem

SetupScreen, SettingsOverlay, HistorySidebar, PlaybackBar, and SearchBox have zero component integration tests. Changes to these components rely solely on manual QA.

Scope

• Component integration tests using @testing-library/react with mocked Tauri API
• Each component gets a test file covering the happy path and key edge cases
• Mock store and IPC responses for isolated testing

Acceptance criteria

• SetupScreen: renders device check, handles model selection, completes setup flow
• SettingsOverlay: opens, edits settings, saves, closes
• HistorySidebar: renders items, search filters, delete works
• PlaybackBar: play/pause, seek, volume control
• SearchBox: input updates, clear button, debounce behavior