Backend: notifications now show a plain "-" for an absent name, vendor, or
device type (was empty string / "(unknown)" / "Unknown"), via a single
UNKNOWN_PLACEHOLDER constant.
Frontend:
- Empty/unknown values render as an em dash everywhere, centralised in a new
Placeholders.emptyValue constant (replaces inline '—' and '(unknown)').
- Route paths moved to a new Routes class, used by the router and every
navigation call site.
- Device event type modelled as a DeviceEventType enum mirroring the backend
(NewDevice/DeviceSeen) instead of bare string comparisons.
- Hardcoded EdgeInsets/SizedBox spacing replaced with existing Insets tokens.
Tests and formatting updated; all backend and frontend tests pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Introduce a headless `flutter test` suite (83 tests) covering models,
utilities, every API endpoint, and the five screens, with shared helpers
and fixtures so new tests stay terse.
API endpoint methods are statically-dispatched extensions on the
BackendAPI singleton, so they cannot be mocked via `implements`. Mock at
the Dio HTTP-adapter layer (http_mock_adapter) instead, enabled by two
small @visibleForTesting seams: BackendAPI.dioForTesting swaps the
singleton's Dio, and BackendReachability.forceOnlineForTesting() forces a
deterministic online state so polling widgets load.
Add frontend/run_tests.sh and document it in CLAUDE.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
