refactor(ci): configure ddtest services explicitly

[gnufede]

Summary

Stacked follow-up to #19870 that removes the standalone scripts/ddtest-infer-service helper while preserving the pre-import service override that ddtest requires.

Changes

• Add explicit ddtest_service values to every ddtest-enabled suite in tests/suitespec.yml, tests/contrib/suitespec.yml, tests/llmobs/suitespec.yml, and tests/appsec/suitespec.yml.
• Have scripts/gen_gitlab_config.py require the metadata and emit _DD_PYTEST_XDIST_INFERRED_SERVICE directly on each generated ddtest run job.
• Remove the shell command substitution and delete scripts/ddtest-infer-service.
• Add generator coverage for the emitted service variable.

This keeps the variable available before Riot starts pytest, when the controller imports ddtrace, while making the expected suite-level service visible and reviewable in suitespec instead of reimplementing package discovery in a shell helper.

Testing

• scripts/lint suitespec-check
• scripts/gen_gitlab_config.py
• scripts/run-tests -s --venv 1c8641e -- -- tests/internal/test_gen_gitlab_config.py (12 passed)

No customer-facing changelog is required.

[cit-pr-commenter-54b7da]

Codeowners resolved as

Resolved from the full PR diff against gnufede/ddtest-dogfooding using the target branch CODEOWNERS file.
CODEOWNERS team requests not listed below are not required by the current file set.

.gitlab/tests.yml                                                       @DataDog/python-guild @DataDog/apm-core-python
scripts/gen_gitlab_config.py                                            @DataDog/python-guild
tests/appsec/suitespec.yml                                              @DataDog/asm-python
tests/contrib/suitespec.yml                                             @DataDog/python-guild
tests/internal/test_gen_gitlab_config.py                                @DataDog/apm-core-python
tests/llmobs/suitespec.yml                                              @DataDog/ml-observability
tests/suitespec.yml                                                     @DataDog/python-guild

[cit-pr-commenter-54b7da]

Circular import analysis

⚠️ Existing circular imports

There are 3 circular imports that already exist on the base branch and have not been changed by this PR.

ddtrace.llmobs -> ddtrace.llmobs._evaluators -> ddtrace.llmobs._evaluators.format -> ddtrace.llmobs._experiment -> ddtrace.llmobs
ddtrace.errortracking._handled_exceptions.bytecode_injector -> ddtrace.errortracking._handled_exceptions.callbacks -> ddtrace.errortracking._handled_exceptions.collector -> ddtrace.errortracking._handled_exceptions.bytecode_reporting -> ddtrace.errortracking._handled_exceptions.bytecode_injector
ddtrace.appsec._asm_request_context -> ddtrace.appsec._iast._iast_request_context_base -> ddtrace.appsec._iast._iast_env -> ddtrace.appsec._iast.reporter -> ddtrace.appsec._exploit_prevention.stack_traces -> ddtrace.appsec._asm_request_context

[cit-pr-commenter-54b7da]

Dependency direction analysis

⚠️ Existing dependency direction violations

There are 240 dependency direction violations that already exist on the base branch and have not been changed by this PR.

Show existing violations (showing 5 of 240 highest severity)

ddtrace.internal.tracemethods -×-> ddtrace.trace  (internal-core -> product:tracing, score=135)
ddtrace.llmobs._integrations.langgraph -×-> ddtrace.trace  (product:llmobs -> product:tracing, score=133)
ddtrace.llmobs._integrations.google_adk -×-> ddtrace.trace  (product:llmobs -> product:tracing, score=133)
ddtrace.profiling.scheduler -×-> ddtrace.trace  (product:profiling -> product:tracing, score=133)
ddtrace.internal.opentelemetry.context -×-> ddtrace.trace  (product:opentelemetry -> product:tracing, score=133)

To see all violations, download the layers-base.json and layers-pr.json artifacts from this CI job and run:

uv run --script scripts/import-analysis/layers.py compare layers-base.json layers-pr.json