- Add scanError field and scannedSuccessfully flag to SecretScanResult
- File read errors no longer falsely report as "clean"
- Callers can distinguish clean files from scan failures
- Update getScanSummary to track filesWithErrors count
- SecretsDetectedError now reports files that couldn't be scanned
- Add tests verifying error handling behavior for file access issues
Refs #337
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>