fix(parsing): correct UPDATE_OBJECT PackedGuid, cape textures, and missing asset guards

- Fix MOVEMENT update type to use readPackedGuid() instead of readUInt64() (WotLK 3.3.5a)
- Add desync diagnostic logging to UPDATE_OBJECT parser for future debugging
- Register MSG_MOVE_SET_COLLISION_HGT (0x518) as skip handler
- Fix cape texture lookup to only try .blp extension variants (4 files)
- Add fileExists() guards for underwear textures referencing missing BLP files (4 files)
- Add spell visual impact→cast M2 path fallback
- Skip WMO doodad instance creation when model load fails
- Demote spell caster position warning to debug level

src/core/appearance_composer.cpp

@@ -123,12 +123,12 @@ PlayerTextureInfo AppearanceComposer::resolvePlayerTextures(pipeline::M2Model& m
             else if (baseSection == 4 && !foundUnderwear && colorIndex == charSkinId) {
                 for (uint32_t f = csF.texture1; f <= csF.texture1 + 2; f++) {
                     std::string tex = charSectionsDbc->getString(r, f);
-                    if (!tex.empty()) {
+                    if (!tex.empty() && assetManager_->fileExists(tex)) {
                         result.underwearPaths.push_back(tex);
                         LOG_INFO("  DBC underwear texture: ", tex);
                     }
                 }
-                foundUnderwear = true;
+                foundUnderwear = !result.underwearPaths.empty();
             }
 
             if (foundSkin && foundHair && foundFaceLower && foundUnderwear) break;