Replace 9 nearly-identical catch blocks in
RegionService.ProcessRegionAsync with a single catch (Exception ex)
that delegates to RegionFailureClassifier.Classify, returning a
typed (category, errorMessage) pair. Preserves all original error
messages stored in region summary files; failure-path call into
HandleProcessingFailureAsync is unchanged.
Net source delta: -38 lines in RegionService, +71 lines in new
RegionFailureClassifier (pure static), +10 unit tests covering
each category, precedence, status-code propagation, null guard.
Tests: 68 unit (was 58) + 5 smoke + 3 stub-contract integration
tests pass.
Co-authored-by: Cursor <cursoragent@cursor.com>
Oleksandr Bezdieniezhnykh