Distribution pole asset class with custom fragility curve support

[m1muralid]

Changes Made:

• Added DistributionPole asset class in asset.py
• Implemented custom fragility curve functionality in custom_distribution.py
• Updated probability_builder.py to support both standard scipy distributions and custom rv_continuous distributions
• Completed unit testing for new functionality

[codecov]

Codecov Report

❌ Patch coverage is 94.16667% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 98.00%. Comparing base (a82d49b) to head (f611e81).
⚠️ Report is 9 commits behind head on main.

Files with missing lines	Patch %	Lines
tests/test_probability_builder.py	87.27%	7 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main      #32      +/-   ##
===========================================
- Coverage   100.00%   98.00%   -2.00%     
===========================================
  Files           10       13       +3     
  Lines          212      350     +138     
  Branches         6        6              
===========================================
+ Hits           212      343     +131     
- Misses           0        7       +7     

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