[mhemmer-cern]

Move the event QA histograms from Utils/EventHistograms.h into EMPhotonEventCut so the histograms use the cut's actual settings. EventHistograms.h is removed; all users now call the member functions addEventHistograms(), fillEventInfo<0|1>() and fillAccepted().

EMPhotonEventCut:

• Add track and FT0C occupancy cuts (SetTrackOccupancyRange, SetFT0COccupancyRange), applied in IsSelected(). Default is no cut. Skipped at compile time if the event table has no occupancy columns.
• Add an optional Q vector cut (SetRequireGoodQvec, SetQvecDetectors, SetQvecHarmonic, SetMaxQvec). Off by default and skipped at compile time if the event table has no Q vector columns.
• hCollisionCounter: fill the occupancy bins (10, 11), add a "good Q vector" bin (14), move "accepted" to bin 15. The Z vertex bin now uses the configured range instead of a fixed |z| < 10 cm.
• Fix: all tasks filled "accepted" at bin 12, which is the "EMC MB Readout" bin.

New Utils/EventUtilities.h (namespace o2::aod::pwgem::pm::utils::event) with the QvecEstimator/Harmonics enums, getQvec(), isQvecGood() and compile-time checks for Q vector and occupancy columns.

Tasks:

• Pass the occupancy configurables to the event cut and remove the duplicated manual occupancy checks. Collision Filters are kept.
• taskPi0FlowEMC, taskPhotonFlow, taskFlowReso: remove the local Q vector enums, getQvec switch, isQvecGood and getAllQvec, and enable the Q vector cut through the event cut. processPCMMixed in taskPi0FlowEMC now also applies the Q vector check, like the other mixed-event processes.
• taskFlowReso: cfgTrackOccupancyMin/Max are now applied (they were defined but unused).
• Call DefineEMEventCut() before booking the histograms in Pi0EtaToGammaGamma(MC).h and TaggingPi0(MC).h.
• calibTaskEmc: remove the unused Q vector and harmonics enums.

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 1199 warnings, 🔕 176 disabled

[jokonig]

Looks good to me. Thanks a lot for the work!