fix(Engine): Fix segment condition evaluation across all system locales

[emyller]

Fix segment condition evaluation across all system locales.

Changes

• Apply locale-independent parsing to numeric strings in segment conditions

How to reproduce

LANG=de_DE.UTF-8 LC_ALL=de_DE.UTF-8 dotnet test

Test failure example

Failed: EngineTest.Unit.Segments.SegmentEvaluatorTest.TestSegmentConditionMatchesTraitValue(
  _operator: "EQUAL", 
  traitValue: 1,23, 
  conditionValue: "1.23", 
  expectedResult: True
)
Expected: True
Actual:   False

Note

CI uses C.UTF-8 locale (period decimal separator). This bug could affect German, French, Spanish, Italian, Portuguese, and other locales using comma as decimal separator.

Review effort: 1/5

[khvn26]

👍

See comment here: #175 (comment), validated in @khvn26's review.