feat(flagd-core): add disabled flag evaluation e2e scenarios

[jonathannorris]

Summary

• Adds tests/e2e/features/disabled.feature with a scenario outline covering boolean, string, integer, float, and object disabled-flag evaluation
• Adds tests/e2e/test_disabled.py with a local evaluator fixture loaded with disabled flag definitions and a scenarios() call against the feature file

Why no flagd_core.py changes

The analogous Java PR (open-feature/java-sdk-contrib#1800) needed a FlagdCore.java change because returning reason=DISABLED is new documented behavior (see ADR). Python's in-process evaluator already returns reason=DISABLED with the caller's code default since the evaluator was extracted in #377, so no implementation change is required here. This PR adds the BDD coverage to verify that behavior against all evaluation types.

Related Issues

Closes #393
Relates to: open-feature/flagd#1965

[gemini-code-assist]

Code Review

This pull request updates the test-harness subproject commit in providers/openfeature-provider-flagd/openfeature/test-harness to a newer version. There are no review comments, and I have no additional feedback to provide.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.23%. Comparing base (daafd73) to head (2006b8f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #395      +/-   ##
==========================================
- Coverage   96.20%   91.23%   -4.97%     
==========================================
  Files          47       17      -30     
  Lines        1741      468    -1273     
==========================================
- Hits         1675      427    -1248     
+ Misses         66       41      -25     

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