Two clean-ups:
- `fai_system_ai_editor.dart` uses the new `RadioGroup<T>`
ancestor pattern Material 3 introduced after Flutter 3.32.
Same UX (three radios for off/redacted/full), no
deprecation warnings, `flutter analyze` is now zero-issue
for the whole project.
- New `install_install_planned_test.dart` asserts that
installing a `planned` seed entry surfaces a clear,
human-readable error class (no panic, no silent success).
Locks in the failed-precondition path Studio's
friendly-error mapper depends on.
Integration test suite is now 3 scenarios:
- capabilities_test.dart: system.approval+kind tag
- install_install_planned_test.dart: planned-install error
All run against a fresh `fai serve` subprocess via
HubFixture, ~2 s total.
Signed-off-by: flemming-it <sf@flemming.it>
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>
