Implement _PreferenceWritingModifier and update PreferenceValues

[Kyle-Ye]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 43.49442% with 152 lines in your changes missing coverage. Please review.
✅ Project coverage is 27.22%. Comparing base (9afbb33) to head (6a8460e).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...re/Data/Preference/PreferenceWritingModifier.swift	0.00%	72 Missing ⚠️
.../Data/Preference/PreferenceTransformModifier.swift	0.00%	34 Missing ⚠️
...iftUICore/Graphic/Color/PreferredColorScheme.swift	0.00%	30 Missing ⚠️
...enSwiftUICore/Data/Preference/PreferenceList.swift	94.91%	6 Missing ⚠️
...iftUICore/Data/Preference/PreferenceCombiner.swift	0.00%	5 Missing ⚠️
...SwiftUICore/Data/Preference/PreferenceBridge.swift	0.00%	2 Missing ⚠️
Sources/OpenSwiftUICore/Graph/GraphHost.swift	33.33%	2 Missing ⚠️
...UICore/Graphic/Color/PreviewColorSchemeTrait.swift	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #746      +/-   ##
==========================================
- Coverage   27.23%   27.22%   -0.01%     
==========================================
  Files         626      627       +1     
  Lines       38201    38262      +61     
==========================================
+ Hits        10403    10417      +14     
- Misses      27798    27845      +47     

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