All eight LD#_LANE / ST#_LANE mnemonics across .B/.H/.S/.D (32 forms).
New NEON_LANE_B/H/S/D encodings split the lane index across Q (bit 30),
S (bit 12) and size (bits 11:10) per element size; the list length and
load/store bit are fixed in the entry bits. All 11 representative forms
(every element size, structure count, and lane extremes) byte-exact vs
llvm-mc and decode-clean; 461 tests green.