Add dynamic memory-based asset caching and aggressive loading

- Add MemoryMonitor class for dynamic cache sizing based on available RAM
- Increase terrain load radius to 8 tiles (17x17 grid, 289 tiles)
- Scale worker threads to 75% of logical cores (no cap)
- Increase cache budget to 80% of available RAM, max file size to 50%
- Increase M2 render distance: 1200 units during taxi, 800 when >2000 instances
- Fix camera positioning during taxi flights (external follow mode)
- Add 2-second landing cooldown to prevent re-entering taxi mode on lag
- Update interval reduced to 33ms for faster streaming responsiveness

Optimized for high-memory systems while scaling gracefully to lower-end hardware.
Cache and render distances now fully utilize available VRAM on minimum spec GPUs.

CMakeLists.txt

@@ -69,6 +69,7 @@ set(WOWEE_SOURCES
     src/core/window.cpp
     src/core/input.cpp
     src/core/logger.cpp
+    src/core/memory_monitor.cpp
 
     # Network
     src/network/socket.cpp