v11.10: Engine-faithful VXL lighting + zoom-aware SS

VXL viewer overhaul

Engine-faithful lighting, crisper supersampling, and several bugs you may
have hit if you spent time in the VXL viewer.

Engine-faithful lighting + RA2/TS presets

• The VXL viewer now uses the actual TS/RA2 voxel light vectors (from Set_Voxel_Light_Angle(45)), and the light is fixed to the model instead of the camera. Orbiting no longer re-lights the unit — same as in-game. Two new preset buttons in the VXL Lighting dialog: RA2 light and TS light.
• The light indicator overlay rotates with the camera so it always points at the side that's actually lit.
• Huge thanks to tomsons26 for sharing the original engine source for Set_Voxel_Light_Angle from both TS and RA2 — without that reference, deriving the authentic light vectors and confirming the camera-vs-world frame would have been guesswork.

Side-color recoloring fixed under VPL

• The house-color swatches (palette indices 16..31) were silently doing nothing whenever a VPL was loaded — the default for RA2/YR voxels. Now works correctly in both VPL and synthetic-shading paths.

Palette swap under VPL no longer corrupts colors

• Swapping palettes on the fly (Load PAL, Ctrl+[/]) on a VPL-lit voxel used to render with stale, mismatched colors. The splat cache now picks up palette changes immediately.

Zoom-aware supersampling + seam fix

• Zooming into a voxel no longer makes it blocky. At >100% zoom the splat automatically raises its effective SS factor toward the on-screen pixel coverage (up to 16x).
• Thin seams between voxels at high SS (visible at 8x / 16x after the zoom-aware change) are gone.
• Supersampling = Off is honored at every zoom (no auto-bump).

Custom side-color picker: live preview

• Adjusting the custom house-color in the picker now retints the player live as you drag the sliders. Cancel reverts; OK commits.

Color picker H / S sliders no longer "stick"

• Hue and Saturation edits/sliders used to be effectively dead on grays, pure white, and pure black. They now preserve the user-intended hue through those edge cases.

Debug controls

• The VXL Lighting dialog gained a small DEBUG group: a toggle for the zoom-aware SS bump (A/B compare) and a Seam pad slider/edit (-64..+64) for diagnosing splat seams. Both grey out when SS = Off.