test(otel): port otel tracestate sampling rate scenarios to parametric

[MilanGarnier]

Summary

• Move the multi-rate tracestate golden-vector matrix and precision-boundary coverage to tests/parametric/test_otel_tracestate_sampling.py; retain the rate-0.5 end-to-end sampling regression.
• Keep the direct end-to-end forwarding, force-keep, and malformed-input coverage; run malformed-input checks under the general sampling scenario.
• Share tracestate thresholds, golden vectors, and forwarding values through tests/otel/utils.py; the OTLP end-to-end cases consume those values without changing their assertions.
• Remove the dedicated otel_sampling_rate_* scenarios.
• Add matching parametric manifest declarations: Go and Ruby remain version-gated, while unsupported tracer targets remain missing_feature.

Validation

• ./format.sh: mypy, ruff, YAML, manifest parsing, and AI Guard checks pass. ShellCheck is blocked by the unrelated directory error at utils/build/docker/internal_server/app.sh.
• git diff --check
• Targeted Python syntax compilation

No broad test suite was run.

[github-actions]

CODEOWNERS have been resolved as:

tests/otel/utils.py                                                     @DataDog/system-tests-core
tests/parametric/test_otel_tracestate_sampling.py                       @DataDog/system-tests-core @DataDog/apm-sdk-capabilities
manifests/cpp.yml                                                       @DataDog/dd-trace-cpp
manifests/dotnet.yml                                                    @DataDog/apm-dotnet @DataDog/asm-dotnet
manifests/golang.yml                                                    @DataDog/dd-trace-go-guild
manifests/java.yml                                                      @DataDog/asm-java @DataDog/apm-java
manifests/nodejs.yml                                                    @DataDog/dd-trace-js
manifests/php.yml                                                       @DataDog/apm-php @DataDog/asm-php
manifests/python.yml                                                    @DataDog/apm-python @DataDog/asm-python
manifests/ruby.yml                                                      @DataDog/ruby-guild @DataDog/asm-ruby
manifests/rust.yml                                                      @DataDog/apm-rust
tests/otel/test_tracing_otlp.py                                         @DataDog/system-tests-core
tests/test_otel_tracestate_sampling.py                                  @DataDog/system-tests-core
utils/_context/_scenarios/__init__.py                                   @DataDog/system-tests-core

[datadog-datadog-prod-us1-2]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 53116d8 | Docs | View more details | Give us feedback!}

[MilanGarnier]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. What shall we delve into next?

Reviewed commit: 3aa2ecb08c

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