EIP-8367 Sunsets Retired BLS Validator Balances to Zero

EIP-8367 proposed: sunset retired BLS validator balances via linear decline to zero over a multi-year window. Companion to EIP-8365, which freezes 0x00 validator balances. Rotating to 0x01 stops reduction, releases full balance. Aims for zero 0x00 balances by post-quantum switch. Schedule constants revisitable per fork. Feedback sought on window length, constants, reduction vs. freezing.