[PWGCF] Use const& and std::move to avoid copies

[vkucera]

Mostly done automatically by Clang-Tidy.

[github-actions]

O2 linter results: ❌ 1666 errors, ⚠️ 2055 warnings, 🔕 49 disabled

[alibuild]

Error while checking build/O2Physics/code-check for 5925580 at 2026-09-02 01:10:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 1156 errors and 4987 warnings.'
Found 1156 errors and 4987 warnings.
++ [[ 1156 -gt 0 ]]
++ cat /sw/BUILD/3bf59b7649317a1d44f95a54e9c167a2fa229c16/O2Physics-code-check/errors.txt
PWGCF/EbyEFluctuations/Tasks/NetProtonCumulants.cxx:60:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/NetProtonCumulants.cxx:188:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:63:9: error: variadic macro 'FILL_QA_HIST_1D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:68:9: error: variadic macro 'FILL_QA_HIST_2D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:73:9: error: variadic macro 'ADD_QA_HIST_1D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:77:9: error: variadic macro 'ADD_QA_HIST_2D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:82:9: error: variadic macro 'ADD_PT_HIST_1D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:90:9: error: variadic macro 'FILL_PT_HIST_1D' used; consider using a 'constexpr' variadic template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:96:8: error: constructor does not initialize these fields: ccdb, fPhiCutExpPosHigh, fPhiCutExpPosLow, fPhiCutExpNegHigh, fPhiCutExpNegLow, funcCutEventsByMultPVvsV0A, funcCutEventsByMultPVvsT0C, funcCutEventsByMultPVvsV0A_anotherTrend [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:581:49: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:705:59: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:706:53: error: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:714:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:715:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:717:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:718:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:720:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:721:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:723:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:724:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:726:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:727:9: error: string concatenation results in allocation of unnecessary temporary strings; consider using 'operator+=' or 'string::append()' instead [performance-inefficient-string-concatenation,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:934:63: error: result of integer division used in a floating point context; possible loss of precision [bugprone-integer-division,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:946:70: error: result of integer division used in a floating point context; possible loss of precision [bugprone-integer-division,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:1156:18: error: narrowing conversion from 'double' to 'int64_t' (aka 'long') [bugprone-narrowing-conversions,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:1160:7: error: Value stored to 'magneticField' is never read [clang-analyzer-deadcode.DeadStores,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:2210:15: error: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:2230:15: error: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:2241:15: error: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/RobustFluctuationObservables.cxx:2241:33: error: narrowing conversion from 'double' to 'bool' [bugprone-narrowing-conversions,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:55:9: error: macro 'ID_BIT_PI' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:56:9: error: macro 'ID_BIT_KA' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:57:9: error: macro 'ID_BIT_PR' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:58:9: error: macro 'ID_BIT_EL' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:59:9: error: macro 'ID_BIT_DE' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:61:9: error: macro 'BIT_IS_K0S' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:62:9: error: macro 'BIT_IS_LAMBDA' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:63:9: error: macro 'BIT_IS_ANTILAMBDA' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:67:9: error: macro 'BIT_POS_DAU_HAS_SAME_COLL' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:68:9: error: macro 'BIT_NEG_DAU_HAS_SAME_COLL' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:69:9: error: macro 'BIT_BOTH_DAU_HAS_SAME_COLL' used to declare a constant; consider using a 'constexpr' constant [cppcoreguidelines-macro-usage,-warnings-as-errors]
PWGCF/EbyEFluctuations/Tasks/kaonIsospinFluctuations.cxx:71:9: error: function-like macro 'BITSET' used; consider a 'constexpr' template function [cppcoreguidelines-macro-usage,-warnings-as-errors]
[0 more errors; see full log]

Full log here.