Add support for pipe input and file extension handling

- Added stdin pipe support for both encode and decode operations
- Implemented file extension-based processing:
  * .dump files: hex dump format with arrow separators
  * .hex files: pure hex string data
  * .xml files: XML content for encoding
- Added 'filename --encode' and 'filename --decode' syntax support
- Enhanced command line parsing for flexible usage
- Updated help text with pipe usage examples

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Data/test_exi.hex

@@ -0,0 +1 @@
+8098021050908C0C0C0E0C5211003200