* feat(standard-tests): make test suite framework-agnostic and publish as public package
Move @langchain/sandbox-standard-tests from internal/ to libs/ for
publishing. The test suite no longer hard-depends on Vitest — test-runner
primitives (describe, it, expect, beforeAll, afterAll) are supplied via
a `runner` config property, letting consumers use any framework.
A convenience sub-export at @langchain/sandbox-standard-tests/vitest
pre-fills the runner with Vitest primitives for zero-config usage.
* format
* no underscore
* adding copies of license files
* adding changesets
* add build step
* fix test
github-actions[bot]