[F2.3] Validate public AST utility exports

[metaphorics]

Question

Implement public AST, is, factory, utils, scanner, visitor, and clone export behavior without exclusions, compatibility shims, or copied reference code.

Blocked by

• Close performance and formal correspondence

Spine anchor

Ive — this leaf serves one bounded product obligation and one evidence ledger.

Acceptance

.outline/gates/F2.3.md reports every gate checked with current, non-pending evidence.