HASTE V1.1.8.7 — DEPTH-AWARE FXAA

Based on V1.1.8.6 Halo-Safe FXAA.

Changes:
- Detects sky-versus-geometry boundaries using depth instead of colour alone.
- For Distant Horizons, checks dhDepthTex0 when normal terrain depth is at the far plane, so DH LOD terrain is not mistaken for sky.
- Reduces FXAA search footprint and blend strength only along sky silhouettes; ordinary edges retain the configured FXAA strength.
- Preserves the stable no-camera-jitter pipeline and all existing water, bloom, lighting, and terrain features.

This is a source-level change intended to reduce the remaining faint silhouette fringe. ZIP integrity and static shader structure are checked; in-game Iris/Distant Horizons rendering still needs validation.
