refactor: modernize single-element JSON handling and log previously-silent catches

[laurentiu021]

Summary

Modernization sweep — code idiom + exception-handling uniformity. refactor:, behavior-preserving, no release.

Changes

• Collection expression for single-element JSON (DriversViewModel, WindowsUpdateViewModel): new[] { root }.AsEnumerable() -> [root] with an explicit IEnumerable<JsonElement> target type. Same result, idiomatic .NET 10.
• Log previously-silent catches: FileShredderService.EnumerateFilesSafe and AboutViewModel's build-date reader had empty catch (IOException)/(UnauthorizedAccessException) blocks. They now Log.Debug(...) like the rest of the codebase (Protocol I: empty catches must log at Debug minimum). Both run once per directory / once per call, so no log flooding.

Notes from the audit (deliberately NOT applied)

• Many .Where(...).ToList() -> [.. ...] suggestions were skipped: they force a var -> explicit-type rewrite for no real gain and .ToList() is already fine.
• LatencySeries.ToList().FindIndex(...) was left as-is: ObservableCollection<T> has no FindIndex, so the audit's proposed .FindIndex would not compile, and the .ToList() is on a cold path.
• LargeFileScanner's per-directory empty catches were left silent intentionally — that loop walks an entire drive and logging every access-denied would flood the log.

Verification

• dotnet build (app + tests): 0 warnings, 0 errors.