Server-side keyboard input events

I propose adding an optional system to Minecraft (Java Edition) that transmits client-side keyboard input events to the server, separate from existing movement and interaction mechanics.

Currently, the server only receives the results of player actions (position, movement, attacks, interactions) but does not receive information about the specific keys being pressed.

I propose adding a lightweight, optional input event layer featuring:

key press / key release events
information about the specific key pressed (e.g., M, H, K, etc.)
no impact on movement physics or game simulation

This would significantly enhance the capabilities of server-side plugins:

creation of server-side keybinds (e.g., opening a menu with a specific key)
convenient UI/GUI systems that don't rely on commands (like `/menu`)
key assignment systems for abilities (ability bindings)
improved server UX without requiring client-side mods
more flexible mini-games and custom mechanics

the system must be optional
it must not affect movement or physics
it should function as an additional event layer on top of the current protocol

Currently, the server sees what the player has done.
This proposal adds the ability to see which key the player pressed, thereby expanding the possibilities for server-side plugins and UI systems.