[PWGCF] FemtoUniverse: Add additional cuts in V0 task

[alicja-pp]

PWGCF/FemtoUniverse/TableProducer/femtoUniverseProducerTask.cxx:

• fill V0 daughters tempFitVar field with DCAxy value.

PWGCF/FemtoUniverse/Tasks/femtoUniversePairTaskTrackTrackMultKtExtended.cxx:

• change description of two configurables to reflect their purpose.

PWGCF/FemtoUniverse/Tasks/femtoUniversePairTaskTrackV0Extended.cxx:

• add additional cuts on track and V0 to set them stricter than in the producer,
• fix more code-check and o2-linter errors. Remaining magic numbers issues appear when the bitmasks are used and should be checked by analyzers that use them, so it can be properly tested.

[github-actions]

O2 linter results: ❌ 11 errors, ⚠️ 0 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for be6d7e4 at 2026-07-28 09:36:

## sw/BUILD/O2Physics-latest/log
c++: fatal error: Killed signal terminated program cc1plus
c++: fatal error: Killed signal terminated program cc1plus
ninja: build stopped: subcommand failed.

Full log here.