Let me replace blocks using commands //replacenear and //replace with item in hand

### The Problem

i have a build with like 5k hoppers and have to replace all the slots with dirt but one and i cant.

### A Solution

what about adding a way for //replacenear hopper ^hopper or any storage block to set the contents of the block?
for example by replacing with item in hand //replacenear hopper ^handitem

### Alternatives

_No response_

### Anything Else?

_No response_

Start by tracing the //replacenear and //replace command entry points and how storage-block contents are represented. Define how ^handitem and ^hopper should affect replacement, then verify that the requested hopper or other storage blocks receive the intended contents while replacement behavior remains correct.

Written by the indexing model from the issue text.