chore: enable strict typing for threads

[P403n1x87]

Description

We enable strict typing checks for the native threads module.

[cit-pr-commenter-54b7da]

Codeowners resolved as

ddtrace/internal/_threads.pyi                                           @DataDog/apm-core-python
mypy.ini                                                                @DataDog/python-guild @DataDog/apm-core-python

[datadog-prod-us1-4]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 33293e8 | Docs | Datadog PR Page | Give us feedback!}

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-05-19 12:58:10

Comparing candidate commit 33293e8 in PR branch chore/threads-strict-typing with baseline commit ddab0a7 in branch main.

Found 0 performance improvements and 5 performance regressions! Performance is the same for 584 metrics, 10 unstable metrics.

scenario:iastaspects-lstrip_aspect

• 🟥 execution_time [+56.139µs; +60.262µs] or [+20.866%; +22.398%]

scenario:iastaspects-translate_aspect

• 🟥 execution_time [+43.627µs; +56.315µs] or [+8.873%; +11.454%]

scenario:iastaspectsospath-ospathbasename_aspect

• 🟥 execution_time [+103.389µs; +110.934µs] or [+24.273%; +26.044%]

scenario:span-start

• 🟥 execution_time [+1.352ms; +1.485ms] or [+8.648%; +9.501%]

scenario:telemetryaddmetric-1-count-metric-1-times

• 🟥 execution_time [+274.841ns; +297.491ns] or [+13.457%; +14.566%]