[PWGJE] jetSpectraCharged: add rhoShift, jetBkgAnalysis: mcp option

[aimeric-landou]

also fix shadowing centrality variable, fix default processes all false

[github-actions]

O2 linter results: ❌ 2 errors, ⚠️ 3 warnings, 🔕 0 disabled

[aimeric-landou]

Linter magic number issue:

    const bool hasLead = jets.size() >= 1;
    const bool hasSub = jets.size() >= 2;

what would be a better way to write this?

[alibuild]

Error while checking build/O2Physics/code-check for 0dde1c6 at 2026-08-31 16:28:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 2 errors and 27 warnings.'
Found 2 errors and 27 warnings.
++ [[ 2 -gt 0 ]]
++ cat /sw/BUILD/21534728beb1b6d2091e9662f6fe8d8b99943934/O2Physics-code-check/errors.txt
PWGJE/Tasks/jetBackgroundAnalysis.cxx:47:8: error: constructor does not initialize these fields: pdgDatabase [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:78:18: error: no header providing "o2::framework::Service" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 27 -gt 0 ]]
++ cat /sw/BUILD/21534728beb1b6d2091e9662f6fe8d8b99943934/O2Physics-code-check/warnings.txt
PWGJE/Tasks/jetBackgroundAnalysis.cxx:41:10: warning: inclusion of deprecated C++ header 'math.h'; consider using 'cmath' instead [modernize-deprecated-headers]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:76:24: warning: initializer for member 'randomNumber' is redundant [readability-redundant-member-init]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:145:77: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:158:119: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:172:98: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:180:94: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:187:81: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:206:121: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:232:75: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:243:117: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:256:98: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:264:94: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:270:79: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetBackgroundAnalysis.cxx:287:119: warning: redundant explicit casting to the same type 'float' as the sub-expression, remove this casting [readability-redundant-casting]
PWGJE/Tasks/jetSpectraCharged.cxx:295:9: warning: boolean expression can be simplified by DeMorgan's theorem [readability-simplify-boolean-expr]
PWGJE/Tasks/jetSpectraCharged.cxx:358:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:368:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:378:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:419:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:429:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:439:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:455:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:465:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:475:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:485:22: warning: statement should be inside braces [readability-braces-around-statements]
PWGJE/Tasks/jetSpectraCharged.cxx:1027:31: warning: boolean expression can be simplified by DeMorgan's theorem [readability-simplify-boolean-expr]
PWGJE/Tasks/jetSpectraCharged.cxx:1110:31: warning: boolean expression can be simplified by DeMorgan's theorem [readability-simplify-boolean-expr]
++ [[ 2 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for cfdf219 at 2026-08-31 18:52:

No log files found

Full log here.