refactor: rename DDGameWrapper loading progress fields

- _field_4d8 → loading_progress (counter, incremented per tick)
- _field_4dc → loading_total (base 0x2AD + 0x38/team + 0x7E overhead)
- _field_4e0 → loading_last_pct (init -100 to force first update)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/openwa-core/src/engine/ddgame.rs

@@ -850,15 +850,14 @@ unsafe fn init_graphics_and_resources(
     }
 
     // ── DDGameWrapper field inits ──
-    (*wrapper)._field_4d8 = 0;
-    // Loading progress total: speech_team_count controls team count scaling.
+    (*wrapper).loading_progress = 0;
     if is_headless {
-        (*wrapper)._field_4dc = 0x2AD;
+        (*wrapper).loading_total = 0x2AD;
     } else {
         let team_count = (*game_info).speech_team_count as u32;
-        (*wrapper)._field_4dc = team_count * 0x38 + 0x7E + 0x2AD;
+        (*wrapper).loading_total = team_count * 0x38 + 0x7E + 0x2AD;
     }
-    (*wrapper)._field_4e0 = 0xFFFFFF9C; // -100
+    (*wrapper).loading_last_pct = 0xFFFFFF9C; // -100: forces first progress bar update
     (*wrapper).speech_name_count = 0;
 
     // ── Audio init (non-headless + sound available) ──

crates/openwa-core/src/engine/ddgame_wrapper.rs

@@ -43,12 +43,12 @@ pub struct DDGameWrapper {
     pub display: *mut DDDisplay,
     /// 0x4D4: DSSound pointer (param3 of constructor)
     pub sound: *mut DSSound,
-    /// 0x4D8: Init 0 (DWORD index 0x136)
-    pub _field_4d8: u32,
-    /// 0x4DC: Calculated value (DWORD index 0x137)
-    pub _field_4dc: u32,
-    /// 0x4E0: Init -100 / 0xFFFFFF9C (DWORD index 0x138)
-    pub _field_4e0: u32,
+    /// 0x4D8: Loading progress counter (incremented per loading tick).
+    pub loading_progress: u32,
+    /// 0x4DC: Loading progress total (base 0x2AD + 0x38 per team + 0x7E overhead).
+    pub loading_total: u32,
+    /// 0x4E0: Last displayed loading percentage (init -100 to force first update).
+    pub loading_last_pct: u32,
     /// 0x4E4-0x14E7: Unknown fields
     pub _unknown_4e4: [u8; 0x14E8 - 0x4E4],
     /// 0x14E8: Speech name table — 360 entries of 0x40-byte C strings.