The backend removed the "Delta N" change-history annotations from
pro-wire-protocol.md (the spec now reflects only the current state), so those
citations no longer resolve. Drop the "Delta #14" references from the `plan`
billing-period doc comments, keeping the still-valid §1 spec reference (the plan
grammar lives in §1). Comment-only; all other §-references verified against the
current spec.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
