Test LangSmith built-in query filtering

[tconley1428]

Summary

• move stack-trace built-in query filtering coverage from the workflow integration test to an interceptor unit test
• retain an end-to-end check for the lightweight Temporal-prefixed query
• stack-trace built-ins can be expensive enough on CI runners to exceed the workflow task deadlock timeout, so their trace-filtering behavior is tested directly at the interceptor boundary

Validation

• focused LangSmith test selection: 2 passed
• targeted Ruff import/format checks, Pyright, and git diff --check