[Feature] Improve handling of conditionally compiled associated types

[graycampbell]

Use Case

Complex usages of conditionally compiled associated types

Feature Proposal

There are still some issues with how conditionally compiled associated types are handled:

• Multiple independent top-level #if blocks with constrained associated types
  • Correct handling requires combining constraints across all active branches to avoid duplicate protocol conformances.
• Nested #if blocks containing associated types
  • Supporting this correctly requires recursive traversal and per-configuration constraint aggregation.
• Cross-branch semantic equivalence of constraints
  • The macro does not attempt to detect when constraints are semantically identical but syntactically different (e.g. Equatable & Hashable vs Hashable & Equatable)

Alternatives Considered

No response

Additional Context

Successor to issue #136. Some handling of conditionally compiled associated types was added in #137 with these known limitations.

Code of Conduct

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