Update requirements and enhance chat UI with new features

- Added new dependencies in `requirements.txt` for improved functionality, including `aiofiles`, `fastapi`, `jinja2`, `markdown`, `pre-commit`, `pydantic`, and `python-multipart`.
- Revamped CSS in `style.css` for a fresh look, including new color variables, improved responsiveness, and enhanced dark mode support.
- Updated `chat.html` to include a viewport meta tag, preconnect for fonts, and improved structure for better accessibility and user experience.
- Implemented auto-resizing for the message input textarea and refined file upload handling with better user feedback.
- Enhanced message rendering with improved copy functionality and added visual indicators for uploads and errors.

Author: TMHSDigital

requirements.txt

@@ -1,9 +1,13 @@
+aiofiles>=23.2.1
+fastapi>=0.110.0
 httpx>=0.27.0
 itsdangerous>=2.1.2
+jinja2>=3.1.2
+markdown>=3.4.0
+pre-commit>=3.0.0
+pydantic>=2.5.2
 python-dotenv>=1.0.1
+python-multipart>=0.0.6
 pytest>=8.0.0
 pytest-cov>=5.0.0
-pre-commit>=3.0.0
-fastapi>=0.110.0
-uvicorn[standard]>=0.29.0
-markdown>=3.4.0 
+uvicorn[standard]>=0.29.0