Burn the surplus RetroPGF

A temp check proposes burning the roughly 500 million OP overallocated to RetroPGF, keeping distributions at the 140 million OP currently projected through year 5, per an erratum correcting an earlier 700 million figure. Genesis projections intended all RetroPGF and Ecosystem Fund OP to be distributed by the end of Year 4, but only about 40 million OP, or ~4.7%, had been distributed after nearly two years. Without burning, RPGF would make up over ~75% of pending unlocks at year 5, so continuing it afterward would instead rely on protocol revenue shares and a 1% to 2% inflation share.