[PWGLF] Debug analysis

[PaolaVT]

Histograms:

• Split HistogramRegistry into registry + registryFrac for output handling
• Replace static string_view arrays and switch-based filling with
  std::array<std::shared_ptr<TH3/TH2>> for dE/dx, binning, and
  particle fraction histograms, indexed by centrality class
• Particle fraction histograms now binned per centrality class (10+MB)
  for both momentum and pT axes
• Add centrality-differential dE/dx vs pT histograms (hDedxVspTMomentumVsCent)

Track selection:

• Add passesTrackSelectionNoDCA() separated from full DCA selection,
  enabling DCA template filling for primary fraction studies
• Add minITSnClusters configurable and propagate to custom track cuts
• Enable phi cut by default (applyPhiCut = true)

PID:

• Replace independent per-species nsigma cuts with bestPIDHypothesis()
  (exclusive closest-nsigma assignment) to avoid double counting

[github-actions]

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