* Update existing CPython test harness sources for 3.15
Synchronize existing Tools and native-harness tests with canonical CPython 3.15.0 while retaining their capability gates. No runtime support is added.
Assisted-by: OpenAI Codex: model version unavailable
* Sync capability-gated perf-map and readline tests
Retain upstream missing-capability gates. This source sync adds neither native providers nor runtime validation.
Assisted-by: OpenAI Codex: model version unavailable
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Co-authored-by: Codex <codex@openai.com>
