Fix: normalize movement vector for 1.21.5+ (fixes #831)

[EIHEI2]

Description

This PR fixes the jittery movement issue reported in #831 for Minecraft 1.21.11.

Problem

Starting from Minecraft snapshot 25w02a (1.21.5+), the vanilla movement vector is normalized. However, Controlify was only limiting the vector length to 1 without normalizing it, causing inconsistent movement behavior, especially noticeable on multiplayer servers.

Solution

Added preprocessor directive to normalize the movement vector for versions >= 1.21.5, matching vanilla behavior. This ensures smooth, consistent movement across all directions.

Changes

• Modified to use for 1.21.5+ targets
• Preserves the old behavior for earlier versions to maintain compatibility

Testing

• Fixes jittery movement on Hypixel and other multiplayer servers
• Maintains analogue input sensitivity (not forced to full speed)
• Diagonal movement now matches vanilla behavior