GTR017 — Normalize boolean case (codemod)

Contract: validity restoration (runtime no-op).

Claim

True/False → true/false is a runtime no-op wherever the lenient model already accepted the value.

Proof

Every Galaxy boolean read goes through galaxy.util.string_as_bool — str(string).lower() in ("true", "yes", "on", "1") (lib/galaxy/util/__init__.py:1104-1108).