* Add mapping for application media type in OpenAI responses client
* Enhance multimodal input samples: Add PDF testing functionality and fix image sample
* Standardize filename handling and add multimodal samples
- Standardized filename extraction logic between chat and responses clients
- Both clients now omit filename when not provided (no default fallback)
- Added Azure Responses API multimodal sample with PDF support
- Cleaned up Azure Chat sample to focus on supported features only
- Fixed test comment placement for better code documentation
- Updated README with clear API capability differences
* Enhance multimodal input samples with image and PDF handling
- Refactor image and PDF handling in `azure_chat_multimodal.py` and `openai_chat_multimodal.py` to use new utility functions.
- Add `load_sample_pdf` and `create_sample_image` functions for better test asset management.
- Remove redundant code for creating sample images and PDFs.
- Introduce a sample PDF file in `sample_assets` for testing purposes.
* Fix formatting in OpenAI chat client
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Co-authored-by: Dmytro Struk <13853051+dmytrostruk@users.noreply.github.com>
Christian Glessner