Preserve Python and Node symbols in memory flamegraphs

[not-matthias]

Summary

• Capture per-process perf maps and Python JIT unwind data alongside native memory artifacts.
• Enable V8 perf maps for memory runs while preserving existing NODE_OPTIONS.
• Document native-allocation coverage and runtime limitations.

Verification

• cargo test --release --bin codspeed writes_keyed_artifacts_and_metadata_for_a_streamed_mapping
• cargo fmt --all --check
• Local Python 3.12 perf-trampoline and Node 22 memory runs produced perf maps and resolved language frames when parsed offline.

[codspeed]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 33 untouched benchmarks
⏩ 4 skipped benchmarks¹

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_{Comparing cod-3654-support-memory-flamegraphs-for-pythonnode (98a1d37) with main (080ed5f)}

Footnotes

1. 4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩