Add comprehensive documentation and code comments

This commit adds extensive documentation to the Mistral OCR CLI project:

- Add API.md with detailed API response format documentation
- Add CHANGELOG.md to track version changes
- Add CONTRIBUTING.md with guidelines for contributors
- Enhance README.md with more detailed usage examples and troubleshooting
- Add proper docstrings to all Python modules and functions
- Update requirements.txt with development dependencies
- Improve setup.py with better metadata

These changes make the project more accessible to users and contributors.

setup.py

@@ -1,10 +1,24 @@
 from setuptools import setup, find_packages
+import os
+import re
+
+# Read version from __init__.py
+with open(os.path.join('mistral_ocr', '__init__.py'), 'r') as f:
+    version_match = re.search(r"__version__\s*=\s*['\"]([^'\"]*)['\"]", f.read())
+    version = version_match.group(1) if version_match else '0.1.0'
+
+# Read long description from README.md
+with open('README.md', 'r', encoding='utf-8') as f:
+    long_description = f.read()
 
 setup(
     name="mistral-ocr",
-    version="0.1.0",
+    version=version,
     description="A CLI tool for performing OCR on documents using Mistral AI",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
     author="Mistral OCR Team",
+    url="https://github.com/yourusername/mistral-ocr-python",
     packages=find_packages(),
     install_requires=[
         "requests>=2.25.0",
@@ -23,6 +37,8 @@ setup(
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
+        "Topic :: Text Processing",
+        "Topic :: Utilities",
     ],
     python_requires=">=3.7",
 )