feat: major engine overhaul - scene demo with lighting, sphere, ground

- Scene Demo: cube + sphere + ground plane with proper lighting
- Audio: XAudio2 dynamic loading + WAV playback
- Physics: expanded collision system
- Renderer: improved pipeline with materials
- UI: extended widget system
- VisualScript: enhanced serializer + block interactions
- ASM: optimized math/memory/profiling routines
- Window: mouse input + scroll support

Engine/VisualScript/block_executor.h

@@ -9,6 +9,7 @@
 #define MAX_VARIABLES 256
 #define MAX_CALL_STACK 32
 #define MAX_EXEC_STACK 1024
+#define MAX_LOOP_STACK 32
 
 // 变量
 typedef struct {
@@ -23,6 +24,14 @@ typedef struct {
     Block* return_block;
 } CallFrame;
 
+// 循环帧
+typedef struct {
+    Block* loop_block;
+    int counter;
+    int target;
+    Block* after_block;
+} LoopFrame;
+
 // 执行状态
 typedef enum {
     EXEC_IDLE = 0,
@@ -43,6 +52,9 @@ typedef struct BlockExecutor {
     CallFrame call_stack[MAX_CALL_STACK];
     int call_stack_top;
     
+    LoopFrame loop_stack[MAX_LOOP_STACK];
+    int loop_stack_top;
+    
     Block* current_block;
     double wait_timer;