Merge origin/feature/migrate-and-test-DDS-targets into feature/qt6-migration-basis-modules

Resolve merge conflicts between Qt6 migration basis modules and DDS test/target migration:

- codegen_simple.py: Keep Qt6 includes (generic_dtc_impl.h, service header)
- svc_ftc_impl.cpp.grantlee: Adopt DDS branch conditional logic ({% if ft.isCoreFt %})
- generic_dtc.h/.impl.h (include/ and Lts/): Keep Qt6 full-path includes, explicit wrapper methods for consistency
- connext.h: Add logger initialization for Requester/Replier (DDS branch enhancement)
- new_docker_build.sh:
  - Add GROUP4_TARGETS for DDS tests
  - Smart DOCKER_IMAGE selection (prebuilt vs ubuntu:26.04)
  - Add BUILD_TESTING=ON to cmake
  - Add Group 4 (DDS Tests) build step

Strategy: Preserve Qt6 migration decisions while incorporating DDS test/target changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-legatus/tests/test_migration_stubs.cpp

@@ -104,7 +104,7 @@ TEST(MigrationStubs, ComponentMonitorDtcCompiles)
 
 TEST(MigrationStubs, CoreDtcCompiles)
 {
-    using namespace DDS::Core::Interface;
+    using namespace Core::Interface;
     EXPECT_TRUE(true);
 }
 
@@ -113,7 +113,7 @@ TEST(MigrationStubs, CoreDtcCompiles)
 
 TEST(MigrationStubs, DDSCoreDtcCompiles)
 {
-    using namespace DDS::Core::Interface;
+    using namespace Core::Interface;
     EXPECT_TRUE(true);
 }