Remove the Release 1 pipeline files; point everything at Release 2

new_docker_build.sh and rpmbuild/make_rpm_ubuntu26.py (Release 1
validation-scope driver/producer) did not belong to this branch; their
functional callers are adapted to the Release 2 files:

- rpmbuild/make_rpm_ubuntu26_release2.py: PIPELINE_FILES now packages
  new_docker_build_release2.sh and make_rpm_ubuntu26_release2.py.
- jenkins-ci-rme/jenkins_builder_ubuntu26.sh: runs
  make_rpm_ubuntu26_release2.py with -DBUILD_RTI=ON and the Release 2
  target list (--build_targets; a full-tree build is not possible on
  this tree); staging tar also excludes ./build4*.
- jenkins-ci-rme/release-16-10-2026.sh (local dry run): calls
  new_docker_build_release2.sh; derives the pipeline root from the tree
  layout and exports MIGRATE_PIPELINE_ROOT; uses the prebuilt image when
  present, otherwise the driver installs deps in-container (the R1
  --build-prebuilt-image option does not exist in the R2 driver).
- jenkins-ci-rme/jenkins/Jenkinsfile: coverage stage runs the R2 driver
  with MIGRATE_PIPELINE_ROOT exported (wins over the checked-in .envrc,
  which carries a host-specific path).
- Doc/comment updates: Dockerfile header, install_arcgis.sh, publisher,
  Jenkinsfile descriptions, jenkins-ci-rme/README.md, README.md.

Remaining references to the old names are only in historical migration
reports, which are left as-is.

qt6-after/qt6-migrated-legatus/README.md

@@ -205,7 +205,7 @@ scope again (Release configuration, Ninja, scoped target list) and produces
 | `qt6-release-sources_1.0-1_amd64.deb` | Release 2 scope sources (source files + CMakeLists under the release dirs) |
 | `qt6-release-ctest-runtime_1.0-1_amd64.deb` | Test executables under `/usr/lib/ctest/` (currently empty — the producer looks for a `build4/bin/` dir, which the driver's timestamped `build4_<ts>/` dirs do not match) |
 | `qt6-release-ctest-sources_1.0-1_amd64.deb` | Test sources (files with "test" in the name under release dirs) |
-| `qt6-release-build-pipeline_1.0-1_amd64.deb` | In-tree pipeline files (the producer's `PIPELINE_FILES`: `new_docker_build.sh`, `Dockerfile`, `jenkins-ci-rme/*`, `rpmbuild/make_rpm_ubuntu26.py`, `CMakeLists.txt`) under `/usr/src/pipeline/` |
+| `qt6-release-build-pipeline_1.0-1_amd64.deb` | In-tree pipeline files (the producer's `PIPELINE_FILES`: `new_docker_build_release2.sh`, `Dockerfile`, `jenkins-ci-rme/*`, `rpmbuild/make_rpm_ubuntu26_release2.py`, `CMakeLists.txt`) under `/usr/src/pipeline/` |
 
 (Version string = `--lts-version` + `-` + `--build-number`, default `1.0-1`.)