KOS_OP_VAR_INPLACE

• Style: EXTRA (OPERAND, VAR). Row a0 = the bare KosOperand selector; a1 = constant pool index of the variable name.

• Stack: [..., rhs] → [...]. Augmented assignment through the frame namespace: obj = deref(name); obj OP= rhs; store back. No value pushed.

• Compiler form: Emitted by the inplace specials (set! with an arithmetic rhs, incr!, …). Lowers to FAST_INPLACE when the name has a fast slot. With a constant rhs, compress fuses the CONST into VAR_INPLACE_CONST instead.