HASTE V66 — GRASS ROOT-PINNED WIND FIX

Base: Haste Shader V1.1.8.7 Depth-Aware FXAA (the user's confirmed no-black-ring build).

Fix:
- Corrected local plant height reconstruction from at_midBlock.
- Iris defines at_midBlock.xyz as the offset from each vertex to its block centre in 1/64-block units; therefore its Y offset is inverted relative to vertex height.
- The previous formula mapped the bottom vertices to maximum sway and the top vertices to zero/less sway, making grass appear to slide as a whole.
- The corrected formula maps the block bottom to 0 and the top to 1, so grass/crops/flowers are pinned at their roots and bend progressively toward their tips.
- Double-height plants keep a continuous height weight from lower-half base through upper-half tip.
- Preserved the previous depth-aware FXAA, water/Distant Horizons behaviour, bloom and other shader systems.

Validation: archive integrity and targeted source checks performed. Minecraft/Iris in-game rendering was not available for verification.
