Fill the test gaps in the app package, raising coverage from 82% to 97%:
- format_test.go: cover all display helpers moved in T3.5 (StatusText,
EventText, Display*), previously untested.
- operations_test.go: add RunNow not-found and refused-while-running
paths, DeleteJob/SetEnabled not-found errors, UpdateJob re-enable,
runtimeForLocked lazy-recreate, UpdateSettings invalid-config branches,
and prependLog activity-list capping.
All tests are Fyne-free, using a temp-dir store, a fake runner seam, and
a fake Clock. go vet and go test -race pass across the module.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
mixeme