Add MrGameEng.AI utility-AI module; format codebase with CSharpier
New MrGameEng.AI module (ResponseCurve, Consideration, UtilityAction,
UtilityAi selector, Blackboard) plus CSharpier formatting applied across
the whole engine. Documents the CSharpier convention in CLAUDE.md.
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Test projects become executables (OutputType=Exe) as required by v3.
Satisfy the new xUnit1051 analyzer by passing TestContext cancellation
tokens in the generator compilation test.