Fix WMO wall collision, normal mapping, POM backfill, and M2/WMO rendering performance

- Fix MOPY flag check (0x08 not 0x01) for proper wall collision detection
- Cap MAX_PUSH to PLAYER_RADIUS to prevent gradual clip-through
- Fix WMO doodad quaternion component ordering (X/Y swap)
- Linear normal map strength blend in shader for smooth slider control
- Enable shadow sampling for interior WMO groups (covered outdoor areas)
- Backfill deferred normal/height maps after streaming with descriptor rebind
- M2: prepareRender only iterates animated instances, bone dirty flag
- M2: remove worker thread VMA allocation, skip unready bone instances
- WMO: persistent visibility vectors, sequential culling
- Add FSR EASU/RCAS shaders

src/rendering/terrain_manager.cpp

@@ -911,6 +911,8 @@ bool TerrainManager::advanceFinalization(FinalizingTile& ft) {
             wmoRenderer->setDeferNormalMaps(false);
             wmoRenderer->setPredecodedBLPCache(nullptr);
             if (ft.wmoModelIndex < pending->wmoModels.size()) return false;
+            // All WMO models loaded — backfill normal/height maps that were skipped during streaming
+            wmoRenderer->backfillNormalMaps();
         }
         ft.phase = FinalizationPhase::WMO_INSTANCES;
         return false;