Refactor menu rendering and asset registry structure

- Updated SoftwareRenderer to incorporate MenuHeaderBand for handling spear variant menus and improved backdrop drawing.
- Refactored asset registry imports to organize menu-related assets under a dedicated menu structure.
- Enhanced game session snapshot tests to validate menu theme restoration for spear variant games.
- Added tests for classic menu presentation module to ensure palette consistency with canonical constants.
- Implemented tests for spear asset registry to verify correct menu VGA index resolutions.
- Created unit tests for MenuHeaderBand to validate functionality in rendering menu headers and sidebars.
- Adjusted HUD module imports to align with new menu structure.

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_dart/README.md

@@ -238,6 +238,17 @@ The presentation module should treat its image-returning methods as optional hoo
 
 - return a `VgaImage` when that surface has variant-specific art,
 - return `null` when the presentation intentionally has no image for that concept,
+
+### Palette Conversion Guardrail
+
+When mapping target RGB menu tones to a VGA palette index (for example, preserving Wolf classic dark-red theme), resolve nearest colors from `ColorPalette.argbFromVgaIndex()` values.
+
+Do not use `ColorPalette.findClosestPaletteIndex()` for this specific workflow, because its channel interpretation is legacy-oriented and can produce hue-swapped matches (for example, red targets resolving to blue-ish indices).
+
+In short:
+
+- For variant-defined menu colors: use explicit palette indices from `MenuPresentationModule`.
+- For host-defined fallback RGB tones: find nearest VGA index by comparing RGB distance against `argbFromVgaIndex()` output.
 - use `mappedPic(...)` only for legacy numeric menu art lookups that still matter for a renderer path.
 
 ### Wiring A Fully Custom Registry