HASTE V1.1.8.6 — HALO-SAFE FXAA

Based on V1.1.8.5 Sky Silhouette Diagnostic, where disabling FXAA removed the outline.

Changes:
- Re-enabled FXAA in Low through Ethereal; Hasteful remains off for minimal cost.
- Lowered default/profile FXAA strength to 0.55.
- Corrected the FXAA direction-reduction factor from 1/32 to the conventional 1/8.
- Limited the directional sample span from 8 pixels to 2 pixels, reducing broad mixing across sky/terrain silhouettes.
- Raised the low-contrast threshold to avoid filtering small luminance changes in haze and sky gradients.
- Capped maximum filter contribution at 0.75.

The purpose is to restore useful spatial edge smoothing while avoiding the broad dark/bright fringe seen when FXAA was enabled. This build has passed ZIP and source-structure checks, but still needs an in-game Iris test; no claim of rendered validation is made.
