kip-311: add PN compatibility budgets

[ian0371]

Proposed changes

This updates KIP-311 to define explicit PN compatibility budgets during mixed-version operation.
During mixed-version operation, legacy transaction propagation may still depend on the EN-PN-CN path.
If PN were collapsed into EN for discovery and dial accounting, ordinary EN peers could fill the EN target and prevent a v3.0 EN from discovering or dialing available PNs.

Types of changes

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• Bugfix
• KIP Proposal
• KIP Improvement

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Related issues

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Further comments

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