Improve GraphQL naming conflict error to identify conflicting entities and operations

[Copilot]

Why make this change?

When autoentities includes tables whose names differ only by singular/plural form (e.g. dbo.Category and dbo.Categories), DAB fails startup with a vague error that doesn't identify the other conflicting entity, the generated GraphQL names, or how to resolve the conflict.

What is this change?

• RuntimeConfigValidator.ValidateEntitiesDoNotGenerateDuplicateQueriesOrMutation: Replaced HashSet<string> operation tracking with Dictionary<string, string> (operation → owning entity). Checks all operations (not short-circuit) to collect every conflicting name, then builds a structured error message including:
  • Both conflicting entity names
  • All conflicting GraphQL operation names
  • Singular/plural type names (for table/view entities)
  • Actionable resolution instructions

Before:

Entity dbo_Category generates queries/mutation that already exist

After:

GraphQL naming conflict detected.

Entities:
  dbo_Categories
  dbo_Category

The above entities generate conflicting GraphQL operation names:
  category_by_pk
  categories
  createCategory
  updateCategory
  deleteCategory

GraphQL type names in conflict:
  Singular type: Category
  Plural type: Categories

Configure distinct GraphQL singular and plural names for one of the entities to resolve this conflict.

How was this tested?

• Integration Tests
• Unit Tests
  • Updated ValidateExceptionForDuplicateQueriesDueToEntityDefinitions helper to verify both conflicting entity names appear in the message
  • Updated all 6 existing duplicate-detection test call sites
  • Added ValidateAutoEntitiesWithSingularPluralNameCollisionGenerateDuplicateQueries covering the exact dbo.Category / dbo.Categories scenario

Sample Request(s)

N/A — error message improvement only; no API behavior changes.

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