.NET: Make WorkflowBuilder more intuititve

[lokitoth]

Before this change, Executorish binding has some unintuitive behaviour. When a user adds an executor with an id of an executor that already exists, we silently replace it, if the user provides it inside of add_edge. When a user introduces an executor via an unbound id, the user must bind it via BindExecutor, even though the registration is created implicitly when an edge id added.

The change will remove the invisible update in favor of a "best efforts" check of type and instance equality.

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[Copilot]

Pull Request Overview

This PR improves the WorkflowBuilder's executor binding behavior by replacing silent replacement with validation checks. Instead of automatically overwriting existing executors with the same ID, the system now validates that new bindings match existing ones by type and instance reference.

Key changes:

• Added validation to prevent binding executors with same ID but different types or instances
• Enhanced ExecutorRegistration to track raw executor data for comparison
• Added comprehensive test coverage for the new binding validation behavior

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
WorkflowBuilderSmokeTests.cs	Adds test cases covering late binding, implicit binding, and validation scenarios
WorkflowBuilder.cs	Implements validation logic to check type and instance equality before binding
ExecutorRegistration.cs	Adds RawExecutorishData property to store original executor data for comparison
ExecutorIsh.cs	Adds RawData property and updates Registration to include raw data

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