Reduce DomainEventHandlerRegistry constructor complexity

[Copilot]

DomainEventHandlerRegistry had accumulated enough inline registration and configuration binding logic to exceed the complexity threshold. This change keeps the registration behavior intact while moving the constructor back to a small orchestration role.

• Constructor split into focused helpers

  • Extracted configuration binding into GetEventHandlerConfiguration(...)
  • Extracted service registrations into:
    • RegisterEventHandlers()
    • RegisterProjections()
    • RegisterResolvers(...)

• Registration behavior preserved

  • Existing named configuration registrations remain unchanged:
    • EventHandlerConfiguration
    • EventHandlerConfigurationDomain
    • EventHandlerConfigurationOrdered
  • Existing Lamar registrations for handlers, projections, dispatchers, resolvers, and IDomainEventFactory<IDomainEvent> are still wired the same way

• Minor cleanup

  • Centralized registration names as private constants to remove duplicated string literals
  • Improved helper-local naming for readability

Example of the resulting constructor shape:

public DomainEventHandlerRegistry()
{
    Dictionary<String, String[]> eventHandlersConfiguration =
        this.GetEventHandlerConfiguration($"AppSettings:{MainRegistrationName}", MainRegistrationName);
    Dictionary<String, String[]> eventHandlersConfigurationDomain =
        this.GetEventHandlerConfiguration($"AppSettings:{DomainRegistrationName}", DomainRegistrationName);
    Dictionary<String, String[]> eventHandlersConfigurationOrdered =
        this.GetEventHandlerConfiguration($"AppSettings:{OrderedRegistrationName}", OrderedRegistrationName);

    this.RegisterEventHandlers();
    this.RegisterProjections();
    this.RegisterResolvers(eventHandlersConfiguration, eventHandlersConfigurationDomain, eventHandlersConfigurationOrdered);
    this.AddSingleton<IDomainEventFactory<IDomainEvent>, DomainEventFactory>();
}

Warning

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If you need me to access, download, or install something from one of these locations, you can either:

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Complexity] Method DomainEventHandlerRegistry::DomainEventHandlerRegistry has 58 lines of code (limit is 50)</issue_title>
<issue_description>Codacy ID: a6099cf7ba0c893b98fc656657da66d1

File: TransactionProcessor/Bootstrapper/DomainEventHandlerRegistry.cs
Line: 32
Rule: Complexity (Warning)
Commit: 5b8f3e64d731c7b181b225e9d4117fda74faa3ac

Message: Method DomainEventHandlerRegistry::DomainEventHandlerRegistry has 58 lines of code (limit is 50)

**Code Snippet:**
```csharp
        public DomainEventHandlerRegistry() 
```

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Complexity] Method DomainEventHandlerRegistry::DomainEventHandlerRegistry has 58 lines of code (limit is 50) #1419

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