[PWGJE] add sel8FullPbPb support to jet cross-section efficiency

[Hamwooseok]

This PR adds "sel8FullPbPb" support to the charged-jet cross-section efficiency task.
The goal is to evaluate the PbPb-specific occupancy selections together with the existing event-selection efficiency chain, including their effect before and after the reconstructed-collision ("hasColl") requirement.

Changes:

• Add "sel8FullPbPb' support in both selection-order variants.
• Add separate QA chains for the time-range and ITS-ROF occupancy selections.
• Add optional truth-to-reco validation histograms for the "multFT0C" activity proxy.

Notes:
The truth-side PbPb occupancy selections use configurable multFT0C proxies for reconstructed FT0C-amplitude and ITS-track criteria. The default 5000/8000 thresholds are not calibrated truth equivalents of the reconstructed cuts and should be validated or tuned before physics interpretation.

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 2 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for 95622a6 at 2026-09-18 04:38:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 11 errors and 3 warnings.'
Found 11 errors and 3 warnings.
++ [[ 11 -gt 0 ]]
++ cat /sw/BUILD/7f26f16769898bf683e152bc35d15d900ef5e6e6/O2Physics-code-check/errors.txt
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:103:3: error: no header providing "o2::framework::Service" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:150:47: error: no header providing "o2::aod::Collisions" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:151:39: error: no header providing "o2::aod::TracksIU" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:151:54: error: no header providing "o2::aod::TracksExtra" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:153:3: error: no header providing "o2::framework::Partition" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:153:52: error: no header providing "o2::aod::track::flags" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:153:98: error: no header providing "o2::aod::track::PVContributor" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:154:61: error: no header providing "o2::aod::track::collisionId" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:266:29: error: no header providing "TAxis" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:267:12: error: no header providing "size_t" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:519:49: error: no header providing "o2::aod::FT0s" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 3 -gt 0 ]]
++ cat /sw/BUILD/7f26f16769898bf683e152bc35d15d900ef5e6e6/O2Physics-code-check/warnings.txt
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:55:8: warning: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:125:3: warning: initial values in enum 'JetCrossSectionEfficiency::BinPbPbTruthSelectionOnly' are not consistent, consider explicit initialization of all, none or only the first enumerator [readability-enum-initial-value]
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:193:9: warning: boolean expression can be simplified by DeMorgan's theorem [readability-simplify-boolean-expr]
++ [[ 11 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for e1b9007 at 2026-09-18 10:47:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 1 errors and 0 warnings.'
Found 1 errors and 0 warnings.
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/a5ebb380465413b76d771e466b58135b798c4192/O2Physics-code-check/errors.txt
PWGJE/Tasks/jetCrossSectionEfficiency.cxx:157:98: error: no header providing "o2::aod::track::PVContributor" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 1 -gt 0 ]]
++ exit 1
--

Full log here.