HASTE V1.1.8.4 — AO / TERRAIN CONTOUR FIX

Target: terrain outlines / overly dark seams around snow layers and fine foliage.

Changes:
- AO_STRENGTH is now 1.0 in every profile. This preserves vanilla's baked vertex AO instead of multiplying it and deepening block-edge seams.
- Shadow minimum fill defaults to 0.65 to reduce overly black contact/shadow contours without disabling shadows.
- Slightly increased shadow depth bias to reduce self-shadow acne along alpha-cutout foliage and close terrain surfaces.
- Reduced the foliage grazing-angle transmission term and profile strength to avoid bright rims around leaf cards.
- FXAA and the stable V1.1.8.1 rendering path are retained; no temporal jitter/history pass is added.

Validation: archive integrity and static source checks only. This still needs in-game Iris testing; shader compilation/rendering was not available in this environment.
