[PWGLF] Adding discription for analysis and adding event flow and efficiency corrections

[bhattdurgesh921-sys]

Dear @dmallick2 ,
In this PR we have implemented the event-level correction framework for the Δ analysis by adding the Event Loss and Event Splitting calculations, corresponding QA and cut-flow histograms, and the truth-level INEL > 0 selection.

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 4 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for 401a700 at 2026-08-05 16:30:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 4 errors and 0 warnings.'
Found 4 errors and 0 warnings.
++ [[ 4 -gt 0 ]]
++ cat /sw/BUILD/a7b56d8d321c7d74bb74dd6547c8a591165bb857/O2Physics-code-check/errors.txt
PWGLF/Tasks/Resonances/deltaAnalysis.cxx:80:8: error: constructor does not initialize these fields: pdgDB [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
PWGLF/Tasks/Resonances/deltaAnalysis.cxx:86:3: error: no header providing "o2::framework::Service" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGLF/Tasks/Resonances/deltaAnalysis.cxx:458:38: error: no header providing "TH1" is directly included [misc-include-cleaner,-warnings-as-errors]
PWGLF/Tasks/Resonances/deltaAnalysis.cxx:1655:59: error: use 'contains' to check for membership [readability-container-contains,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 4 -gt 0 ]]
++ exit 1
--

Full log here.

[vkucera]

@bhattdurgesh921-sys Don't duplicate PRs. #17317

[vkucera]

@prottayCMT Don't merge untested PRs.