Refactor Fluent Syntax to have a single implementation of each method

[alexanderlinne]

This PR eliminates significant code duplication in the fluent API by restructuring the class hierarchy:

Before: Generic classes like TypesShould<TRuleTypeShouldConjunction, TRuleType> implemented all methods and used ConjunctionFactory.Create() with reflection to instantiate the next fluent element. This led to:

• The same predicate/condition methods duplicated across GivenXXXThat and ShouldRelateToXXXThat classes
• Runtime reflection for instantiation

After:

• Abstract base classes (e.g., AddTypePredicate<TNextElement, TRelatedType, TRuleType>, AddTypeCondition<TNextElement, TRuleType>) contain the shared method implementations
• Sealed leaf classes (e.g., GivenTypesThat, TypesShould) inherit from these bases and implement a simple CreateNextElement() factory method that directly instantiates the next class

Benefits:

• ~3,000 lines of code removed
• No more reflection-based instantiation in the fluent chain
• Sealed classes prevent unintended inheritance and enable compiler optimizations
• Single source of truth for each fluent method

[codecov-commenter]

Codecov Report

❌ Patch coverage is 86.15385% with 90 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.35%. Comparing base (92ae901) to head (c767974).

Files with missing lines	Patch %	Lines
.../Members/MethodMembers/AddMethodMemberCondition.cs	50.00%	18 Missing ⚠️
.../Members/MethodMembers/AddMethodMemberPredicate.cs	48.57%	18 Missing ⚠️
...T/Fluent/Syntax/Elements/Types/AddTypePredicate.cs	73.43%	17 Missing ⚠️
...T/Fluent/Syntax/Elements/Types/AddTypeCondition.cs	87.32%	9 Missing ⚠️
...uent/Syntax/Elements/Members/AddMemberCondition.cs	78.94%	4 Missing ⚠️
...uent/Syntax/Elements/Members/AddMemberPredicate.cs	76.47%	4 Missing ⚠️
...lements/Members/FieldMembers/FieldMembersShould.cs	0.00%	4 Missing ⚠️
...ents/Members/FieldMembers/GivenFieldMembersThat.cs	0.00%	4 Missing ⚠️
...ers/FieldMembers/ShouldRelateToFieldMembersThat.cs	0.00%	4 Missing ⚠️
...opertyMembers/ShouldRelateToPropertyMembersThat.cs	0.00%	2 Missing ⚠️
... and 5 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #444      +/-   ##
==========================================
+ Coverage   73.69%   77.35%   +3.66%     
==========================================
  Files         260      275      +15     
  Lines       16463    14411    -2052     
  Branches     1337     1337              
==========================================
- Hits        12132    11148     -984     
+ Misses       3912     2844    -1068     
  Partials      419      419              

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