M1: Define canonical help model (ModuleHelp/CommandHelp/ParameterHelp/ExampleHelp)

[jeffpatton1971]

Create the minimal internal object model used as the contract between parsing and rendering.

Definition of done

• Add POCOs (records/classes) for:

  • ModuleHelp (Name, Culture, Commands[])
  • CommandHelp (Name, Synopsis, Description, Parameters[], Examples[], Notes, Links[])
  • ParameterHelp (Name, TypeName?, Required?, Position?, Description?)
  • ExampleHelp (Title?, Code, Remarks?)
  • LinkHelp (Text?, Uri)

• Model is serializable-friendly and deterministic-friendly (collections are lists, ordering well-defined).

Acceptance checks

• Unit test verifies default construction + property assignments.
• No PowerShell dependency in Core.

[jeffpatton1971]

see 8bc8695