langchain==1.2.7

Changes since langchain==1.2.6

release: langchain 1.2.7 (#34854) feat: dynamic tool registration via middleware (#34842) fix(langchain): strip trailing whitespace from the summarization prompt (#34835) fix(langchain): improve grammar in SummarizationMiddleware system prompt (#34834) docs(langchain): nit (#34788) chore(deps): bump the uv group across 5 directories with 5 updates (#34785) chore(deps): bump the uv group across 8 directories with 6 updates (#34773) chore(core, langchain): add version consistency check pre-commit hooks (#34782)