[PWGLF] Feat/antin cex task update

[FabiolaLP]

Clean up unused histograms and extend the antineutron CEX task and output tables with new analysis variables.

[github-actions]

O2 linter results: ❌ 3 errors, ⚠️ 20 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/staging for 11677b1 at 2026-05-13 21:25:

## sw/BUILD/O2Physics-latest/log
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:845:38: error: 'vtxNAll' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNAll'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:846:38: error: 'vtxNCh' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNCh'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:847:38: error: 'vtxNNeut' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNNeut'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:848:38: error: 'vtxNPi0' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNPi0'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:849:38: error: 'vtxNGamma' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNGamma'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:850:38: error: 'vtxNN' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNN'?
ninja: build stopped: subcommand failed.

Full log here.

[alibuild]

Error while checking build/O2Physics/o2 for 11677b1 at 2026-05-13 21:28:

## sw/BUILD/O2Physics-latest/log
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:845:38: error: 'vtxNAll' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNAll'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:846:38: error: 'vtxNCh' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNCh'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:847:38: error: 'vtxNNeut' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNNeut'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:848:38: error: 'vtxNPi0' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNPi0'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:849:38: error: 'vtxNGamma' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNGamma'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGLF/TableProducer/Nuspex/nucleiAntineutronCex.cxx:850:38: error: 'vtxNN' was not declared in this scope; did you mean 'o2::aod::antin_cex::vtxNN'?
ninja: build stopped: subcommand failed.

Full log here.

[FabiolaLP]

Closing this PR because the branch got polluted while resolving conflicts. I will open a clean PR with the same intended changes.