feat: unify system status codes

kernel/src/Api/LibSyscall.hpp

@@ -115,15 +115,15 @@ namespace montauk::abi {
     // Decrements refcount; actually unmaps when refcount reaches 0.
     inline int Sys_UnloadLib(uint64_t handle) {
         int slot = GetCurrentSlot();
-        if (slot < 0) return -1;
+        if (slot < 0) return GenericFailure;
 
         int libSlot = (int)handle - 1;
-        if (libSlot < 0 || libSlot >= MaxLibsPerProcess) return -1;
+        if (libSlot < 0 || libSlot >= MaxLibsPerProcess) return InvalidArgument;
 
         g_libLocks[slot].Acquire();
         if (!g_libTable[slot][libSlot].inUse) {
             g_libLocks[slot].Release();
-            return -1;
+            return InvalidArgument;
         }
 
         g_libTable[slot][libSlot].refcount--;
@@ -144,7 +144,7 @@ namespace montauk::abi {
         }
 
         g_libLocks[slot].Release();
-        return 0;
+        return Success;
     }
 
     // Resolve a symbol in a loaded library.