Shaders: Slice B — Register stylized presets in MaterialPresetLibrary

[fernandotonon]

Part of #743 (Epic: Shaders). Depends on Slice A (shader assets must compile).

Goal

Register the stylized looks as presets in MaterialPresetLibrary so they flow into the existing preset → CLI → MCP → GUI surface automatically.

Work

• Extend presetNames() (src/MaterialPresetLibrary.cpp ~line 140) with the grouped stylized set: "Toon", "Toon + Outline", "Outline", "Rim Light", "Matcap", "Hologram", "X-Ray", "Gooch", "Flat Shaded", "Vertex Color".
• In applyPreset() (dispatch ~174–219), route stylized names to a new helper applyStylizedPreset(mat, look) that clones/instantiates the matching Stylized.material technique, sets tunables (toon band count, rim color/power, matcap texture, outline width/color, gooch warm/cool), then calls RTShaderHelper::finalizeShaderGenMaterial + mat->compile(/*autoManageTextureUnits=*/false).
• Reuse the existing MaterialPresetCommand undo path and presetApplied signal unchanged.
• Bundle a matcap texture in media/materials/textures/ for the Matcap preset.

Gotchas

• compile(false) to preserve pass/slot layout (same as PBR presets).
• Verify a stylized preset on a skinned mesh (Rumba Dancing.fbx) animates correctly — RTSS skinning via finalizeShaderGenMaterial/createShaderBasedTechnique.

Acceptance

• Each stylized name applies without crashing and renders the expected look in the viewport.
• Applies cleanly to skinned meshes; animation deformation correct.
• Undo restores the prior material; reapply is idempotent.
• --list-presets and the GUI grid show the new names (auto via presetNames()).