docs/spec: close Go verifier findings on Anchor Format §1 escaping rules, verifier-compatibility README, and Acta crosswalk (#536) - #537

Awaiting 1 independent maintainer approval(s) of current head 563a8c3ffc8ac276f5f1c9cf70013c8176a1c6d7; found 0. Branch rules and specification governance also apply.

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