Implement Opacity Effect

[Kyle-Ye]

Close #349

[codecov]

Codecov Report

❌ Patch coverage is 11.02362% with 113 lines in your changes missing coverage. Please review.
✅ Project coverage is 27.40%. Comparing base (581a7e0) to head (2682c6a).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
Sources/OpenSwiftUICore/Render/OpacityEffect.swift	15.38%	66 Missing ⚠️
...ICore/Animation/Transition/ContentTransition.swift	0.00%	47 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #572      +/-   ##
==========================================
+ Coverage   23.61%   27.40%   +3.78%     
==========================================
  Files         526      526              
  Lines       30484    30604     +120     
==========================================
+ Hits         7200     8387    +1187     
+ Misses      23284    22217    -1067     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.