Cache FVM and pub in CI and use repo-relative Windows icon paths

- Add GitHub Actions cache for `.pub-cache` and `.fvm_cache` and wire CI env vars
- Pass `MyRepoRoot` into Inno Setup and use it for `SetupIconFile`
- Change `msix_config.logo_path` to a relative path in `pubspec.yaml`
ec766f2546Dara Adedeji committed on 3/11/2026, 10:43:19 PMparent7b9277f
4 files changedLine totals unavailable