fix: normalize assembly level calculation across all API endpoints

Resolve inconsistency where api/status/model reported one fewer assembly
level compared to hierarchy analysis and shell analysis APIs. Modified
SafeCalculateAssemblyLevels to include root assembly in level count.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CreoManager.cpp

@@ -489,7 +489,8 @@ int CreoManager::SafeCalculateAssemblyLevels(wfcWAssembly_ptr assembly) {
             }
         }
         
-        return max_level;
+        // Add 1 to include root assembly level, consistent with hierarchy analysis
+        return max_level + 1;
         
     }
     catch (...) {