fix: preserve target-typed UDT lifecycle semantics

[luisleo526]

Summary

• target bare na to the exact authored UDT across declarations, assignments, selections, function/method returns, and persistent callable clones
• resolve globals, sibling members, loop binders, method receivers, and lvalue aliases by lexical identity instead of a raw-name UDT union
• preserve primitive, collection, and drawing bindings when same-spelled UDTs exist elsewhere

Validation

• full pytest suite: 2,154 tests collected, exit 0 with native compile checks enabled
• Pyodide differential gate: 277/277 fixtures (263 success fixtures, 14 expected rejections)
• frozen exact-915 inventory: 903 OK / 12 expected errors, zero status drift
• all 4 generated-output deltas compile and replay with byte-identical native trade tapes versus merged main
• private exhaustive 2^2 interaction matrix: 4/4 cells green; all-on 19/19 semantic probes green; production tree exactly matches 858562d
• independent final review: GO after same-name receiver and collection-element adversarial probes

This is a correctness milestone. The affected graded tapes are identical, so it intentionally does not claim a tier-score increase.