Clear Dependabot high alerts (pyo3)

[thomasrockhu-codecov]

Summary

• Bump pyo3 to 0.29.x to clear GHSA-36hh-v3qg-5jq4.
• Mark SqliteReportBuilder as #[pyclass(unsendable)] for pyo3 0.29 Sync requirements.

Test plan

• cargo check --workspace / CI passes
• Confirm Dependabot highs clear after merge

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.22%. Comparing base (215b5fc) to head (627d278).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #70   +/-   ##
=======================================
  Coverage   98.22%   98.22%           
=======================================
  Files          21       21           
  Lines        6025     6025           
=======================================
  Hits         5918     5918           
  Misses        107      107           

Components	Coverage Δ
core	98.32% <ø> (ø)
bindings	74.07% <ø> (ø)
python	100.00% <ø> (ø)

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[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks

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_{Comparing th/cve-pyo3 (627d278) with main (215b5fc)}