Generate generic <T> overloads for IID_PPV_ARGS pattern on COM methods

[Jevan Saks (jevansaks)]

Summary

Auto-detect COM methods with the IID_PPV_ARGS pattern (a Guid* parameter immediately followed by a void** [ComOutPtr] parameter) and generate generic <T> overloads where the GUID is derived from typeof(T).GUID and the output pointer is typed as T.

Closes #374
Fixes #1604

Example

Before — callers must construct and pass the IID manually:

shellItem.BindToHandler(pbc, in bhid, typeof(IStream).GUID, out object streamObj);
IStream stream = (IStream)streamObj;

After — the generic overload handles it:

shellItem.BindToHandler<IStream>(pbc, in bhid, out IStream stream);

Generated overload shapes

Mode	Signature	Constraint
Marshaling (AllowMarshaling=true)	BindToHandler<T>(..., out T ppv)	where T : class
Non-marshaling (AllowMarshaling=false)	BindToHandler<T>(..., out T* ppv)	where T : unmanaged

Changes

• GeneratorOptions.cs — Added FriendlyOverloadOptions.ComOutPtrGenericOverloads (default true)
• settings.schema.json — Added friendlyOverloads.comOutPtrGenericOverloads for opt-out
• Generator.cs / Generator.Invariants.cs — Extract IUnknownHelperMethods template method names to avoid duplicating QueryInterface<T>
• Generator.FriendlyOverloads.cs — Pattern detection (DeclareComOutPtrGenericOverloads) and code generation (BuildComOutPtrGenericOverload)
• COMTests.cs — 5 new tests for marshaling/non-marshaling, opt-out, template precedence, and IntPtr mode

Design decisions

• Only matches void** (not typed pointers like ID2D1Effect**) — typed outputs already have their specific type
• One IID_PPV_ARGS pair per method max to avoid overload explosion
• CoCreateInstance<T> template retained for co-creatable class CreateInstance<T> integration
• Template-based overloads take precedence over pattern-based ones
• Skipped when UseIntPtrForComOutPointers is active (ppv is IntPtr, not castable)