World: add world/sky material colour modulation

Port Amalgam's modulation approach: obtain IMaterialSystem from the already
loaded materialsystem.so (VMaterialSystem080) and walk materials with
FirstMaterial/NextMaterial/GetMaterial. ColorModulate the "World textures"
group (sky names excluded) and the "SkyBox textures"/sky-named group.

The walk runs only when the enabled groups or colours change, restores white
when disabled, and re-applies after level changes. Before touching materials,
GetNumMaterials() and the first material's name/group are sanity-checked so a
wrong vtable slot logs and aborts instead of walking garbage.

GUI: "World tint" card with world/sky toggles and RGB sliders; config section
[worldtint].

1 files changed, 1 insertions, 0 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index 375cd5a..dfe4e57 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -584,6 +584,7 @@ static void do_move(int seq, float frametime) {
     aimbot_reset_lock();
     silentaim_reset_lock();
     fullbright_invalidate();
+    world_tint_invalidate();
   }
 
   if (feature_active(FEAT_SPREAD)) {