feat: Add version file and include in HTTP request user-agent

[chyroc]

• Created a version file to store the current SDK version
• Enhanced HTTP requests to include SDK version, language, and system version in the user-agent header
• Improved traceability and debugging with detailed user-agent information in requests

[codecov]

Codecov Report

Attention: Patch coverage is 90.62500% with 3 lines in your changes missing coverage. Please review.

Project coverage is 74.91%. Comparing base (8dcc15f) to head (47d1a13).
Report is 27 commits behind head on main.

Files with missing lines	Patch %	Lines
cozepy/version.py	86.95%	3 Missing ⚠️

@@            Coverage Diff             @@
##             main      #21      +/-   ##
==========================================
+ Coverage   74.29%   74.91%   +0.61%     
==========================================
  Files          22       24       +2     
  Lines         813      845      +32     
==========================================
+ Hits          604      633      +29     
- Misses        209      212       +3     

Flag	Coverage Δ
	74.91% <90.62%> (+0.61%)	⬆️

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Files with missing lines	Coverage Δ
cozepy/__init__.py	100.00% <100.00%> (ø)
cozepy/request.py	72.72% <100.00%> (+1.02%)	⬆️
tests/test_version.py	100.00% <100.00%> (ø)
cozepy/version.py	86.95% <86.95%> (ø)