## Summary
- Tapping a row in the Undo Log list opens a new `UndoLogDetailScreen`
- Detail screen shows: account ID, action type (with icon/colour), timestamp, source folder, destination folder (move only), and a list of all emails in the transaction (subject + sender)
- Navigation uses go_router nested route `/accounts/undo-log/:actionId` with `state.extra` to pass the `UndoAction` object
- AppBar has an **Undo** button that calls the existing undo service and pops back
## Also fixed
- `flake.nix`: replaced the broken dagger/nix 0.20.8 Nix wrapper (infinite self-exec loop) with a direct 0.21.4 `fetchurl` derivation; wired `DAGGER_HOST` so the pre-commit `dart-check` hook can reach the running engine
- `pubspec.lock`: bumped `meta` 1.17→1.18 and `test` 1.30→1.31 to match what the CI resolver picks up (eliminates spurious generated-files drift in CI)
## Verification
- `task test` — all 492 unit/widget tests pass
- `dart analyze --fatal-infos` — clean (no warnings or infos)
- Pre-commit hooks (including `dart-check` via Dagger) — all passed on commit
Closes#450
Co-authored-by: Thomas SharedInbox <sharedinbox@thomas-guettler.de>
Reviewed-on: https://codeberg.org/guettli/sharedinbox/pulls/461
