Support deterministic Response-to-Result model naming in C#

[Copilot]

Add deterministic naming for C# models ending in Response, replacing the suffix with Result.

• Naming: Compose with acronym normalization: WidgetResponse → WidgetResult, IpResponse → IPResult. Restrict the rule to model types.
• Compatibility: Preserve explicit names, C# customizations, and previous-contract names, including after namespace changes.
• Collision safety: Retain the original suffix when the target conflicts with another type, customization alias, or generated filename—even across namespaces.
• Generated output: Update affected models, client signatures, factories, and serializers.

-public partial class WidgetResponse
+public partial class WidgetResult

• Fixes Support Deterministic Naming for model suffix Response to Result #11993

[azure-pipelines]

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