World: add Fullbright visual feature

- New Visuals card with the usual Active + Bind; default off. Unbound+Active
  is always-on, a bind makes it hold-to-brighten.
- Resolve VEngineCvar004 and set mat_fullbright 1/0 through FindVar (slot 12)
  and ConVar::SetValue(int) (slot 11), bypassing the console cheat gate.
  Fall back to ClientCmd if the cvar interface is unavailable.
- Reapply after map loads/respawns and persist [fullbright] active/bind.
- Log on/off; show an error toast if the cvar cannot be applied.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/hl2h.h b/src/hl2h.h
index 45a297e..e441167 100644
--- a/src/hl2h.h
+++ b/src/hl2h.h
@@ -67,6 +67,7 @@ struct GameInterfaces {
   void *engineserver = nullptr; // IVEngineServer021 (edict access, incl. server entities)
   void *debugoverlay = nullptr; // IVDebugOverlay003 (engine-accurate world->screen)
   void *enginetrace = nullptr;  // EngineTraceClient003 (world vischeck)
+  void *cvar = nullptr;         // VEngineCvar004 (mat_fullbright etc.)
 };
 extern GameInterfaces g_iface;
 
@@ -176,7 +177,8 @@ enum FeatureId {
   FEAT_MELEE = 7,
   FEAT_SPREAD = 8,
   FEAT_ITEM_ESP = 9,
-  FEAT_COUNT = 10
+  FEAT_FULLBRIGHT = 10,
+  FEAT_COUNT = 11
 };
 enum EspOption {
   ESP_OPT_SHOW_NEUTRAL = 0,
@@ -208,7 +210,7 @@ struct FeatureState {
 };
 
 extern FeatureState g_bhop, g_abh, g_jumpbug, g_melee, g_spread, g_esp,
-    g_aimbot, g_triggerbot, g_silentaim, g_item_esp;
+    g_aimbot, g_triggerbot, g_silentaim, g_item_esp, g_fullbright;
 extern bool g_bhop_autostrafe;
 extern bool g_jumpbug_assist;
 extern bool g_spread_no_spread;
@@ -243,6 +245,9 @@ void fix_verified_crc(int seq, uint32_t crc);
 uint32_t usercmd_checksum(const CUserCmd *c);
 bool find_input_global();
 void resolve_netvars();
+bool cvar_set_int(const char *name, int value);
+void fullbright_update();
+void fullbright_invalidate();
 bool resolve_server_netvars();
 int server_entity_health(int idx, int *maxhealth, int *lifestate, void **base_out);
 bool server_set_velocity_z(int idx, float vz);