Adds a new Laravel validation rule to prevent path traversal, hidden files, and invalid filenames in the dynamic proxy configuration feature. Validates filenames to ensure they contain only safe characters, don't exceed filesystem limits, and don't use reserved names.
- New Rule: ValidProxyConfigFilename with comprehensive validation
- Updated: NewDynamicConfiguration to use the new rule
- Added: 13 unit tests covering all validation scenarios
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Co-Authored-By: Claude <noreply@anthropic.com>
