refactor: retype landscape fields from *mut u8 to *mut PCLandscape

crates/openwa-core/src/ddgame.rs

@@ -1,4 +1,5 @@
 use crate::game_info::GameInfo;
+use crate::landscape::PCLandscape;
 use crate::render::RenderQueue;
 use crate::speech::SpeechSlotTable;
 
@@ -35,7 +36,7 @@ pub struct DDGame {
     /// 0x01C: Caller/parent pointer (param_1)
     pub _caller: *mut u8,
     /// 0x020: PCLandscape pointer (copied from DDGameWrapper[0x133])
-    pub landscape: *mut u8,
+    pub landscape: *mut PCLandscape,
     /// 0x024: GameInfo pointer (passed as param_10 to constructor).
     pub game_info: *mut GameInfo,
     /// 0x028: param_9

crates/openwa-core/src/ddgame_wrapper.rs

@@ -1,4 +1,5 @@
 use crate::ddgame::DDGame;
+use crate::landscape::PCLandscape;
 
 /// DDGameWrapper — large wrapper around DDGame.
 ///
@@ -34,7 +35,7 @@ pub struct DDGameWrapper {
     /// 0x4C8: Graphics mode flag (DWORD index 0x132)
     pub gfx_mode: u32,
     /// 0x4CC: PCLandscape object pointer (DWORD index 0x133)
-    pub landscape: *mut u8,
+    pub landscape: *mut PCLandscape,
     /// 0x4D0: DDDisplay/display object pointer (param2 of constructor)
     pub display: *mut u8,
     /// 0x4D4: DSSound/sound object pointer (param3 of constructor)