Add panic error code for heap corruption

Currently, the memory allocator does not trigger a kernel panic on
detected corruption or invalid operations. However, once the heap is
corrupted, the kernel can no longer guarantee safe or correct behavior.

Introduce ERR_HEAP_CORRUPT with a corresponding error message to
prepare for future panic-on-error handling in the memory allocator.

Author: visitorckw

include/private/error.h

@@ -27,6 +27,7 @@ enum {
 
     /* Memory Protection Errors */
     ERR_STACK_CHECK, /* Stack overflow or corruption detected */
+    ERR_HEAP_CORRUPT, /* Heap corruption or invalid free detected */
 
     /* IPC and Synchronization Errors */
     ERR_PIPE_ALLOC,    /* Pipe allocation failed */

kernel/error.c

@@ -22,6 +22,7 @@ static const struct error_code error_desc[] = {
 
     /* stack guard */
     {ERR_STACK_CHECK, "stack corruption"},
+    {ERR_HEAP_CORRUPT, "heap corruption or invalid free"},
 
     /* IPC / sync */
     {ERR_PIPE_ALLOC, "pipe allocation"},