Give the MFT support volume a name of its own

[sawenzel]

This fixes a problem in the MFT support geometry, where a volume and its assembly share a name.

• Volumes with the same name share a ROOT volume number, so consumers keyed on that number see only one of the two.
• In FLUKA the pair collapsed to the assembly's placeholder material, which means BLCKHOLE, so the PEEK support disks deleted every particle entering them.

[alibuild]

Error while checking build/O2/fullCI_slc9 for ab03ec7 at 2026-09-25 10:42:

## sw/BUILD/O2-latest/log
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/TPC/base/src/TPCBaseLinkDef.h:75:56
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/TPC/base/src/TPCBaseLinkDef.h:83:135
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/TPC/base/src/TPCBaseLinkDef.h:84:135
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/Upgrades/ALICE3/ECal/base/src/ECalBaseLinkDef.h:19:48
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/Upgrades/ALICE3/RICH/base/src/RICHBaseLinkDef.h:18:48
Error: missing ; at end of rule at /sw/SOURCES/O2/slc9_x86-64-slc9_x86-64/0/Detectors/Upgrades/ALICE3/MID/base/src/MI3BaseLinkDef.h:18:47


## sw/BUILD/O2-full-system-test-latest/log
command /sw/slc9_x86-64/O2/slc9_x86-64-slc9_x86-64-local4/prodtests/full-system-test/dpl-workflow.sh had nonzero exit code 1
[4680:internal-dpl-ccdb-backend]: [10:41:59][ERROR] CCDBDownloader CURL transfer error - Timeout was reached
[4680:internal-dpl-ccdb-backend]: [10:41:59][ERROR] CcdbDownloader finished transfer http://alice-ccdb.cern.ch/EMC/Calib/FeeDCS for 1550600800023 (agent_id: o2-itsmft-stf-d/o2-itsmft-stf-decoder-workflow@4680 target/Linux_x86_64 init/1790325704560 id/mesosci@pcapiserv08 session/Lt9r6NMt) with http code: 0
[4680:internal-dpl-ccdb-backend]: [10:41:59][ERROR] File EMC/Calib/FeeDCS could not be retrieved. No more hosts to try.
[4680:internal-dpl-ccdb-backend]: [10:41:59][FATAL] Unable to find CCDB object EMC/Calib/FeeDCS/1550600800023
[4680:internal-dpl-ccdb-backend]: [10:41:59][ERROR] Exception while running: Fatal error. Rethrowing.
[4680:internal-dpl-ccdb-backend]: [10:41:59][FATAL] Unhandled o2::framework::runtime_error reached the top of main of o2-itsmft-stf-decoder-workflow, device shutting down. Reason: Fatal error
[ERROR] Workflow crashed - PID 4680 (internal-dpl-ccdb-backend) did not exit correctly however it's not clear why. Exit code forced to 128.
[ERROR]  - Device internal-dpl-ccdb-backend: pid 4680 (exit 128)
[INFO]    - First error: [10:41:59][FATAL] Unable to find CCDB object EMC/Calib/FeeDCS/1550600800023
[ERROR] SEVERE: Device internal-dpl-ccdb-backend (4680) had at least one message above severity 7: Unable to find CCDB object EMC/Calib/FeeDCS/1550600800023


## sw/BUILD/o2checkcode-latest/log
--
========== List of errors found ==========
++ GRERR=0
++ grep -v clang-diagnostic-error error-log.txt
++ grep ' error:'
++ GRERR=1
++ [[ 1 == 0 ]]
++ mkdir -p /sw/INSTALLROOT/e0f650989beb7780e134b6c82a2aec946a666030/slc9_x86-64/o2checkcode/1.0-local3/etc/modulefiles
++ alibuild-generate-module
+ HAS_BIN=
+ HAS_LIB=
+ HAS_CMAKE=
+ HAS_ROOT=
+ '[' 0 '!=' 0 ']'
+ cat
+ printf 'if ![ is-loaded '\''BASE/1.0'\'' ] {\n module load BASE/1.0\n}'
+ echo 'BUILD_REQUIRES=CMake alibuild-recipe-tools defaults-release'
BUILD_REQUIRES=CMake alibuild-recipe-tools defaults-release
+ FULL_BUILD_REQUIRES='MPFR alibuild-recipe-tools CMake double-conversion Python-modules-list googlebenchmark UUID O2-customization bz2 ninja-fortran date ninja safe_int pytorch_cpuinfo json-c defaults-release Alice-GRID-Utils FairCMakeModules'
+ echo 'FULL_BUILD_REQUIRES=MPFR alibuild-recipe-tools CMake double-conversion Python-modules-list googlebenchmark UUID O2-customization bz2 ninja-fortran date ninja safe_int pytorch_cpuinfo json-c defaults-release Alice-GRID-Utils FairCMakeModules'
FULL_BUILD_REQUIRES=MPFR alibuild-recipe-tools CMake double-conversion Python-modules-list googlebenchmark UUID O2-customization bz2 ninja-fortran date ninja safe_int pytorch_cpuinfo json-c defaults-release Alice-GRID-Utils FairCMakeModules
++ env
++ cut -f1 -d=
++ grep -v '^DEFAULT_'
++ grep -v PKGREVISION
[0 more errors; see full log]

Full log here.