Replace dynamic allocations with fixed-size buffers and add module extension filtering

- Use fixed STK_PATH_MAX and STK_MOD_ID_BUFFER throughout for predictable memory
- Filter by platform-specific extensions (.so/.dll/.dylib) with compile-time length
- Add RELOAD event detection and is_module_loaded() helper
- Maintain feature parity across all platforms

include/stk.h

@@ -4,8 +4,10 @@
 #include "stk_version.h"
 #include <stdlib.h>
 
-#define MOD_DIR_BUFFER_SIZE 32
-#define PATH_BUFFER_SIZE 1024
+#define STK_MOD_DIR_BUFFER 256
+#define STK_MOD_ID_BUFFER 64
+#define STK_PATH_MAX 256
+#define STK_PATH_MAX_OS 4096
 
 #ifdef __cplusplus
 extern "C" {