Qt6 Migration: Update stub headers to include generated files

- Updated all include/*/*_dtc.h stub headers to include generated files
  from build4/Lts/Proxies/*/ directories
- Changed ParticipantManagement stub headers to use generated files
- Updated ProjectDataManagement pdm_enums.hpp to include generated file
- Updated Buildings bld_dtc.h to include generated file
- Created BUILD_STATUS_REPORT.md documenting current build state

Migration Status:
- DDS core libraries: ✅ Building successfully (6 libraries)
- Proxies module code: ✅ Migration complete
- Services modules: ⚠️ Pre-existing errors blocking full build
  - ParticipantManagement: Type definition mismatches
  - InfrastructureManagement: Struct/member mismatches
  - ProjectDataManagement: DTC implementation errors

These Services errors are unrelated to Qt6 migration work and require
separate fixes. Once resolved, Proxies module will build automatically.

(cherry picked from commit 5501d1e501)

qt6-after/qt6-migrated-legatus/include/OperatorManagement/opm_dtc.h

@@ -1,43 +1,4 @@
 #pragma once
 
-// STUB-HEADER: Diese Datei wird normalerweise von ddsdtc generiert
-// Für die Migration erstellen wir minimale Implementierungen
-
-#include <QtGlobal>
-#include <string>
-#include <memory>
-
-namespace OperatorManagement
-{
-
-struct User
-{
-  [[nodiscard]] qint32 id() const { return m_id; }
-  [[nodiscard]] std::string name() const { return m_name; }
-
-  qint32 m_id = 0;
-  std::string m_name;
-};
-
-namespace Interface
-{
-class Dtc
-{
-public:
-  // Initialization methods
-  void enableUser() {}
-  void waitForHistoricalDataUser() {}
-  
-  User user(qint32 id) const
-  {
-    // STUB-Implementierung - leerer User
-    User u;
-    u.m_id = id;
-    u.m_name = "Unknown";
-    return u;
-  }
-};
-
-class Ftc;
-} // namespace Interface
-} // namespace OperatorManagement
+// STUB-HEADER: Include generated file from build directory
+#include <Lts/Proxies/OperatorManagement/opm_dtc.h>